Candlewick (a.k.a. Lampwick in other versions) the troublesome boy Pinocchio befriends from The Adventures of Pinocchio, in his introduction it is revealed his real name is Romeo and he got the aforementioned nickname because he was so tall and thin.
The Agent Z books give us a minor character who ended up known as "The Incredible Hulk", as he was overheard slowly reading the words "I... am... The Incredible Hulk" from a comic whilst newly arrived with his family from India and still teaching himself English. What he thought about this nickname is not discussed, but it stuck because nobody could pronounce his given name.
In Ark Angel of the Alex Rider series. Alex encounters 4 thugs which he nicknames "Combat Jacket", "Silver Tooth", "Spectacle" and "Steel Watch".
Amelia Peabody's son Ramses. No, a Victorian Age English couple did not name their son after an Egyptian Pharaoh, but you could be forgiven for thinking they did, given how rarely his real name (Walter) is mentioned in the books.
The main protagonist in American Gods is called Shadow, a nickname he earned when he was young by quietly following adults at the hospital where he spent most of his time. Even in his thirties, he mostly goes by this nickname, occasionally uses an alias, and not once in the entire book is his true name revealed. Toward the end, after he dies but before his afterlife is decided, he takes an opportunity to learn his role in the grand scheme, and has to pay admission with his own name. When the personification of Easter brings him back to life, he remembers what he learned, and remembers having to trade something for that knowledge, but doesn't remember the cost, implying that he no longer realizes Shadow is just his nickname.
Though, if any of you really are curious, a follow up short story reveals that his real name is Balder. Which, really, we should've seen coming.
His wife Laura's full name is given early in the book; if she took his surname, it implies that it's Moon.
The main protagonist of its companion novel, Anansi Boys, has a similar issue. Any nickname his father (Anansi) gives someone tends to stick to a literally supernatural degree, so when his dad called him "Fat Charlie" as a boy, everyone around him would call him that well into adulthood, even though he wasn't particularly overweight.
Almost all of Anne and Gilbert's children in L.M. Montgomery's Anne of Green Gables series are known exclusively by their nicknames. Their first child, Joyce, is called "Joy" during her short life. The next child, James, is known as "Jem". Younger twins Anne and Diana go by "Nan" and "Di", for obvious reasons. Youngest child Bertha Marilla goes exclusively by "Rilla".
Stacey, treasurer of the club. It wasn't until she moved away that the rest of the club even found out that Stacey was a nickname for Anastasia.
Also Jessi and her siblings. Not too bad for Jessi (Jessica) and Becca (Rebecca), but their poor little brother Squirt; even the ghostwriters rarely remembered that his real name was John Phillip Ramsey Jr.(for example, when Jessi adressed a letter to her parents 'Mr. and Mrs. Alex Ramsey').
Kristy, Abby, and many minor characters.
The magicians in The Bartimaeus Trilogy all use nicknames, because they can't control the demons if they know their true name. The demons would prefer their names not to be known either (so they can't be summoned), but use them nonetheless.
Prince Kheldar is referred to as "Silk" throughout The Belgariad, except by those who don't know him well or want to tease him. Garion and Durnik both call Polgara "Pol" almost exclusively, and Garion thinks of Belgarath only as "Mister Wolf" until well into the third book.
Many of Bertie Wooster's cronies go exclusively by nicknames; in Thank You, Jeeves, he is amused to finally learn that the first name of his long-time friend "Chuffy" Chuffnell is Marmaduke.
Almost every character in Glen Cook's The Black Company novels is covered either by this trope or Everyone Calls Him "Barkeep". Justified in-universe as the narration focuses on Company Brothers, who take a new name (usually given by existing Brothers) when they join to symbolically leave their past life behind. In addition, this is Serious Business for wizards, as a sorcerer can lose all his powers by someone invoking his True Name, motivating the most powerful Evil Sorcerors to kill everyone who knows them by anything but their nickname. This happening to The Lady and The White Rose is even the climax of the third book.
Certain characters in the series take this to extremes.
When Croaker is asked for his real name to be put on his Commission as General, it takes him a few minutes to remember it. He specifically avoids mentioning it in the Annals (his narration).
"Stormshadow," is a nickname used to cover a different nickname that she was known by in the North before faking her death.
Tobo and the Daughter of Night don't have real names, only nicknames, owing to the peculiar circumstances surrounding their births and childhoods. "Tobo" is explicitly stated to be a nickname given by his mother until she could reunite with his father and they could agree on a real name. By the time that happens, the boy is a teenager. The Daughter of Night was kidnapped at birth and raised as The Antichrist; her parents never had the opportunity to name her (though her father favors "Chana," her mother argues that it sounds too much like "Kina," the name of the Goddess that the Daughter serves) and her captors have no use for an identity beyond The Daughter of Night. Though the Company does eventually start calling her "Booboo," mostly as a joke.
In The Cat Who series, Qwill's girlfriend Polly Duncan is known by most only as Polly. Possibly no one else in Moose County knows that her Shakespeare-loving father named his daughter Hippolyta. Qwill himself also fits the trope, except that he had his name legally changed; his oldest friend Arch is the only other person in the world who knows that James Mackintosh Qwilleran was born Merlin James Qwilleran.
There are a few of these in the Chalet School books, the earliest example being (the) Robin (aka Cecilia Marya Humphries). Later on there's Bifauxnen Tom Gay (real name Lucinda Muriel, and given that she's an extreme Tomboy, it's understandable why she hates her real name) and Polly Heriot (real name Hildegard).
In Child Of The Owl, Casey's friend (real name Tallulah, after actress Tallulah Bankhead) is known as Booger, due to an incident of picking her nose with a bobby pin back in elementary school. Also, Casey's cousin Pamela is known as 'Pam-Pam'.
Tuppence Beresford (nee Cowley) fromTommy and Tuppence. Her real first name is Prudence, but no-one ever uses it.
Bunch Harmon, Miss Marple's goddaughter in A Murder is Announced, who was "christened Diana by optimistic parents".
Bundle Brent (real name Lady Eileen Brent) in The Secret of Chimneys and The Seven Dials Mystery. Seven Dials also has the minor characters Rupert Bateman, who "had been nicknamed Pongo for no earthly reason whatever" at school and is still addressed as such by his schoolfriends, and Vera Daventry, who everyone calls Socks.
In the Circle of Magic series, characters Trisana Chandler and Sandrilene fa Toren normally go by "Tris" and "Sandry".
In the Clémentine books, because the protagonist got a "fruit name," she only ever calls her little brother by vegetable names, such as "Pea Pod", "Rutabaga" and "Spinach". She is very careful never to present a scene in which his real name is used, making it a weird case of the character only being known by his nickname. Series author, Sara Pennypacker, when asked for the real name by fans, has rigidly insisted that only she and her two children will ever know the character's real name.
Code Name Verity plays this straight with its main character Queenie, who doesn't reveal her name until the end. However, when the narrative shifts to her best friend Maddie, Maddie only ever refers to her by her actual name (Julie).
Queenie claims she never knew the name of her superior, who she only ever refers to as the Machiavellian Intelligence Officer. Maddie reveals this to be false, although she doesn't reveal the man's name either, referring to him as John Balliol, the name of the Scottish king Julie's ancestor William Wallace lost his life defending.
Jebe, the Arrow, in Bones of the Hills. His real name is Zurgadai, but in only known as Jebe because of his great skill with a bow.
In the Russian Death Zone series, most characters and anyone else living in the Five Zones goes by a nickname. Occasionally, their real first name may be revealed, but the full name will usually stay hidden. For example, the leader of the Order is known by all as Commander Hunter, which is a nickname (in English, in fact) given to him by a neo-Nazi gang shortly before the Catastrophe. Only his closest advisors know that his real first name is Savva. On the other hand, all members of the rival organization known as the Ark are required to adopt a German name by their leader Heinrich Hister, the former head of the above-mentioned gang. Another interesting case is Titanium Vine, whose name is Darling. She was found in a Human Popsicle tank with no memory of her identity but a tattoo with "DRG" on her shoulder, hence the name.
Despite being Heterosexual Life-Partners with him for decades, Fred Colon of fame apparently had no idea Nobby Nobbs's real name is 'Cecil Wormsborough St John Nobbs', or even just his real first name until they went undercover in Jingo. Others may know his name (it presumably appears in the Watch pay accounts) but no one ever calls him it, even city nobles knew him as Nobby.
Discworld also features "Cut Me Own Throat" Dibbler, a purveyor of sausages in a bun of questionable nature, is only ever referred to by his catchphrase, or CMOT, or "Throat", if in a hurry. Eventually, however, in Making Money, we learn that CMOT are the initials of his actual name and probably (apart from being told the phrase by a time-travelling Vimes) the in-universe reason why he adopted the nickname in the first place.
Mad: Most people call me Mad. Rincewind: Just "Mad"? That's an... unusual name. Mad: It ain't a name.
A minor character in Jingo is a gang leader called The Artful Nudger ... except to Captain Carrot who calls him William. The Nudger has no idea how Carrot knows his real name - his mother probably wouldn't have known his real name, if he knew who she was - and anyone else using it would be in serious trouble, but Carrot's ... Carrot.
Andrew "Ender" Wiggin from Ender's Game, to the point where he can go around inconspicuously as Andrew Wiggin in Speaker for the Dead. (Granted, that is 3,000 years in the future due to relativistic time travel, but still...). People do occasionally recognize his name as being the same as "the Xenocide's" (a banker even accuses him of using a false ID when he sees it), but because it is so far in the future no one makes the connection.
Also in the later books of the Ender's Game saga many of the characters are from Lusitania, where long Portuguese names are the norm, and just about everyone goes my a nickname. These may be ordinary short forms of their names ("Liberdade Graças a Deus Figueira de Medici" becomes "Libo"), translations ("Estevão Rei Ribeira von Hesse" becomes "Quim," pronounced "king") or unrelated and based off of personal characteristics (Lauro Suleimão Ribeira von Hesse" is called "Olhado" due to his cybernetic eyes.) The full names are usually mentioned once or twice, and then ignored.
Then there's Julian "Bean" Delphiki, Jr. However, this is justified because he grew up on the streets and didn't have a name. Due to his size and perceived worthlessness, another street urchin told him that he isn't "worth a bean". Given that he's a result of a genetic experiment, whose "brothers and sisters" were "terminated" by the Mad Scientist when he was discovered by the authorities. At the end of Ender's Shadow, Bean discovers his biological parents and brother (his best friend from Battle School).
In the Fancy Nancy books, Nancy Clancy's little sister's real name is Josephine, but this is only mentioned maybe once. Otherwise, she's always called JoJo.
Flight to the Lonesome Place has Anna Maria Rosalita, Luis Black, and Marlowe refer to Ronnie by his stage name, The Blue Boy. Anna Maria Rosalita calls him Boy Blue while Luis Black sometimes refers to him as brother Blue.
Toby's real name from the novel The Floor of the Sky is Gwendolyn, the which few people actually know. Apparently, she's been going by that name since she was a toddler (which was indicated to be sixty-nine years ago) when she said, “That sumbitch called me Gwenlum. My name not Gwenlum. My’s Toby.” Said nickname used to be the dog's name.
'Hoodwink' is a nickname he earned as a teenage thief.
'Leader' is the name of The Leader of the Users. His real name is never given.
Fudge in the Judy Blume books is actually named "Farley Drexel Hatcher". At one point, his mother even insists on his brother calling him nothing but "Fudge". His first kindergarten teacher insists on calling him either by one of his legal names or his initials, resulting in Fudge refusing to cooperate with her and having to be transferred to another class. His baby sister Tamara Roxanne is more commonly called "Tootsie" and they only mention her real name in her introduction.
Many of the deceased kids in ghostgirl have a "dead name" that they're frequently called. For example, Piccolo Pam swallowed her piccolo, while "Metal Mike" was listening to metal music while taking his driver's test and crashed, which caused him to have metal shards in his head as well.
The Bears never refer to themselves by their given names, so Nikita (and the reader) only identifies them by their nicknames.
Mister B doesn't have an actual name, so that's what Nikita always calls him.
In Gone with the Wind, Bonnie Blue Butler is really Eugenie Victoria, but everyone calls her Bonnie after the Bonnie Blue Flag because she has blue eyes. Likewise, Aunt Pittypat Hamilton's real name (Sarah Jane) is mentioned once early in the book. Both are extremely easy to miss since the nicknames are used so ubiquitously.
Ginevra "Ginny" Weasley from the Harry Potter series — when she was taken into the Chamber of Secrets, even the professors referred to her as "Ginny Weasley". For years, fans assumed that "Ginny" was short for "Virginia", but Word of God later revealed that her real name was "Ginevra". The only person to ever call her this was an elderly relative in the last book.
This is common with the Weasleys, although most of the time it's pretty easy to guess their full names, as the rest all have traditional English names.
Similarly Voldemort is almost always called "You-Know-Who" or "He-Who-Must-Not-Be-Named" by those who fear him, or "The Dark Lord" by those who follow him. Those who neither fear him or follow him call him Voldemort... which isn't his real name anyway. It was exactly the desired effect, as Voldemort wanted is real name to be forgotten. Dumbledore and Harry refer to him as Voldemort, but use his real name in front of him to upset him. Dumbledore is the only person to call him Tom. Harry calls him Riddle during their final showdown.
Alastor Moody is known as "Mad-Eye" Moody to most people. When Harry first hears Dumbledore call him Alastor in a crowded room, it takes Harry a few seconds to realize who he was speaking to.
The Hogwarts ghosts: Nearly Headless Nick (his real name is Sir Nicholas de Mimsy-Porpington), Moaning Myrtle (whose first name is Myrtle but last name is unknown), Fat Friar, Grey Lady (her real name is Helena Ravenclaw) and Bloody Baron.
In Honor Harrington, Prescott David Tremaine apparently started to be called "Scotty" on his first day at Saganami Island, and twenty two years and innumerable adventures later he's still never referred any other way.
"Mullet Fingers" from Carl Hiaasen's Hoot. He doesn't have egregious amounts of 80s hair growing from his knuckles or anything. He got his nickname by being a Friend to All Living Things and having reflexes fast enough to catch a mullet fish with his bare hands.
Foxface from The Hunger Games trilogy. Katniss gives her the name on the basis that she looks like a fox, and we never learn what her real name is. More than half the tributes are never named.
In the script of the movie, her name was given as Marissa. Unknown whether Suzanne Collins considers this canon.
Many of the characters in I, Claudius are only known by their nicknames (for example, "Caligula" and "Castor"). Roman naming customs were very unimaginative, so several people might have identical or almost-identical names; nicknames make it much easier than trying to figure out which of the eight or nine "Drusus"es someone might be talking about.note Truth in Television; the ancient Romans made use of nicknames for just that reason. In the books, the narrator will usually mention the real name before telling you that that guy will just be known as "Castor" from then on; in the TV series, they generally didn't even do that.
There are several cases of this in the Inkheart books: We are told that "Capricorn" is a name he gave himself, but we never know what his real name is. The same with Orpheus (who gets it double since Farid calls him only "Cheeseface"). The Magpie's real name is Mortola, but she is very rarely refered to that way. "The Adderhead" and "the Laughing Prince/Prince of Sighs" are names given to them by their subjects. Also the Barn Owl, Nettle, Firefox, Sootbird, the Piper, Flatnose, Cockerell, Cloud-Dancer, and the Black Prince.
Even though it's never mentioned that he might have another name, Dustfinger could easily be an example of this. Since his world is full of regular names like Roxanne, Basta, and Minerva, it's probably safe to assume that this is a nickname rather than what his parents named him.
Mortimer is an interesting case of this. While everyone else calls him by his proper name, Dustfinger, Capricorn, and the other characters from Inkheart refuse to call him anything but "Silvertongue", which he doesn't like. He is also known only by a nickname to his daughter, Meggie, who "had never called her father anything but 'Mo'."
Inverted in Jennifer, Hecate, Macbeth, William McKinley, and Me, Elizabeth, in which Jennifer steadfastly ignores a teacher that calls her "Jenny" until she uses her proper name, Jennifer.
Yo-less, Wobbler and Bigmac in the Johnny Maxwell Trilogy. When Johnny talks to Bigmac's social worker, it takes him a minute to remember that she'd know him as Simon.
Jude's eldest child in Jude The Obscure: his mother didn't bother to christen him and simply called him "Little Father Time". Jude and Sue more or less do the same thing.
In the Judy Moody books and the associated Stinky Moody spin-offs, Stink's real name is James, but this is only very rarely mentioned.
Kill Time or Die Trying has many of these. Talk-Shout, Indy, Kevin and even the main character who is addressed only as Brad within the club.
Kantorka (means: daughter of the cantor) in Krabat. Fortunately, because I Know Your True Name also applies (the villain is an evil wizard).
Pagan in Shirley Conran's Lace. Her real name is Jennifer, but she grew up with a nanny who called her "you little pagan" when she misbehaved. Her family eventually started calling her Pagan and the nickname stayed with her throughout her life.
Cameron "Buck" Williams from Left Behind. This may be because he corrects anyone who tries to use his actual name. One character's insistence on using his real name rather than "Buck, because he bucks against journalistic conventions" is used as evidence of her unsympathetic nature.
Legit versions of this trope in that series include Albie (who is named for his hometown Al Basrah) and Razor.
One of the main characters in Lord of the Flies is known only as Piggy, a nickname he hates. His real name is never revealed.
The Rat in The Lost Prince. His real name, Jem Ratcliffe, is mentioned once when he first introduces himself to the protagonist, and then never again.
In the classic children's novel The Machine Gunners the son of the cemetery keeper is known only as "Cem". (A throwaway line in one of the sequels reveals that he inherited his father's position and was still known as "Cem" a good thirty years later.)
Malazan Book of the Fallen: Most professional soldiers in the series are known only by their nicknames, typically assigned during basic training. Examples include Whiskeyjack, Fiddler, Hedge, Bottle, Stormy, Halfpeck, Iron Bars and many more.
In the Sci-Fi novel Malevil, La Menou's actual name is never stated, and she goes by her nickname which means "tiny".
Every character in The Man Who Brought the Dodgers Back to Brooklyn calls Daniel Malone "Squat", a nickname he picked up while playing as the catcher in neighborhood baseball games as a kid. He points out in the narration that the only person who calls him by his real name is his mother.
Son of the Shadows: Known as the Painted Man to most, Chief to his men, he has forgotten his own name, until Liadan (the only one to give him an actual name) reminds him.
In Daughter of the Forest, it's the other way around. Everyone knows the male protagonist as Hugh of Harrowfield, except for those closest to him, who call him Red. More straightforward in the sequel, when he has moved to Ireland: everyone calls him Iubdan ('the little man'), so that hardly anyone remembers that he's actually a Briton called Hugh.
Pumpkin in Memoirs of a Geisha. Chiyo/Sayuri gave her the nickname within a week of meeting her, never mentions her given name, and goes on to mention that it continues to stick even after she takes a new name as a geisha. Which must really suck for Pumpkin, because she spends the latter portion of the book hating Sayuri's guts and deliberately sabotaging her chance with the man of her dreams, since she and Chiyo were forced rivals as girls and Pumpkin's life became very dismal as a result.
In the Midnight Louie books, Max Kinsella's real name is technically Michael Aloysius Xavier Kinsella, but good grief. It's not much a surprise he took the first of each his names and combined them to become the "Mystifying Max".
Many characters in the Mistborn trilogy appear to be examples of this trope, but occasionally do go by their real names. Two characters that are examples are Clubs, who is named for his leg injury, and his nephew Spook, a secondary character in the first book. As he develops both as a character and a member of the thieving crew, he's given the name "Spook" because it's easier to say than his real name, "Lestibournes". He eventually stops using his given name in favor of the one he has earned.
It's revealed that Lestibournes is a nickname itself, meaning something like unwanted child in his slang.
Jace Wayland from The Mortal Instruments. Jace comes from the initials for Jonathan Christopher, which hardly anyone calls him. When his full name is revealed at the end of City of Bones, its significant because it makes Clary think he's her long-lost brother, who also had the initials J.C.
Sticky Washington in The Mysterious Benedict Society series. His real name is "George", so he insists on people referring to him only by the nickname because he doesn't feel that he can live up to the name of "George Washington". However, none of the officials at the Learning Institute for the Very Enlightened will use the nickname, because they feel that "if it isn't official, then it can't be real."
Neil Gaiman's short story October in the Chair features a boy who was bullied by his twin older brothers. They had nicknamed him the Runt and everyone called him this.
Not really a nickname, but Reuven Malter in Chaim Potok's books seems to use his Hebrew name almost exclusively; his "real" first name is Robert, but he's only seen using a few times, and only when dealing with people who aren't Jewish.
Peekay in The Power of One has some typical English name, but it's never used.
Until the 7th book, JP in The Princess Diaries series was known only as The Guy Who Hates It When They Put Corn In The Chili.
This is the default state for elves in the Quantum Gravity'Verse. True Names are very powerful, and so an elf will be known by the last part (usually one-syllable) of his or her name to absolutely everyone except close friends, who will use the first half. This is subtle foreshadowing of the fact that Sarasilien is not the elf's real name—even though he only has a business relationship with most of his coworkers, he still tells all of them his "real" name.
Rabble Starkey: Rabble's real first name is Parable Ann, but for the most part goes by Rabble. Sweet Ho's full first name was Sweet Hosannah. Rabble called her grandmother Gonmie and only later when she asked her mother how to spell the name did she realize it was Naomi.
Beezus from the Ramona Quimby series isn't actually named Beezus, she's named Beatrice. Many of the books don't even tell you that! She's named after their mother's younger sister, whom both girls adore.
One of the books mentions that she got this nickname from Ramona's toddler mispronunciation of Beatrice. She seems to be fine with being called so, although there was one episode in another book where some boys at the park took advantage of the fact that it rhymes with "Jesus".
In the second book, we are introduced to The Gray Man. As a hitman, he understandably likes to keep his real name a secret.
Fade from the Razorland Trilogy - his given first name is revealed midway through the first book, but his family name is never given. He refuses to respond to his given name after being taken in by the College enclave.
Redwall's vermin are often named with uncomplimentary descriptions of their physical features (possibly reaching its peak in Triss with the briefly-mentioned "Fatty" and "Stinky"). In Loamhedge the fan assumption that these were nicknames was made explicit, as the adolescent Redd is told he will soon receive his "proper vermin name".
Urgan Nagru says that he took his official name from the wolf Urgan, whom he claims to have killed and whose pelt he wears. His original name is never revealed. Played with in the Official Fanfiction University, when his wife Silvamord threatens to tell the students what his real name is.
The Reynard Cycle: Even though the Calvarians snicker at the concept, and know Reynard's real name, they consistently call him "The Fox" when referring to him.
In Rumble Fish, the Motorcycle Boy is only known by this nickname and even his teachers use it. His younger brother is one of the few in the neighborhood that even knows his, unstated, real name.
Ditto Two-Bit Matthews in Hinton's The Outsiders, whose real name is known, but only mentioned once by the narrator when introducing him into the story and never again.
Sacré Bleu features the Colorman, who tells people that his first name is "The". You find out later that he was born in 38,000 BC and his name was Two Grunts and a Shrug, which translates to "Poop on a Stick". You can't really blame him.
Give 'Em Hell and Preacher of The Shadow Campaigns are almost always referred to be those monikers. Marcus notes that he sometimes forgets that Preacher has a name that's not "Preacher", and when Janus asks for Captain Vahkerson, it takes everyone a while to figure out he's talking about Give 'Em Hell.
In Shaman of the Undead Brittle is rarely called by his surname, Kruszyński, and only Redhead (who herself is an example) ever calls him by his name, and even that happened perhaps once. Even when we're looking through his eyes, narrative still calls him Brittle.
Flick in Jean Shepherd's short stories, of which A Christmas Story is the most famous adaption. He was based on a real-life childhood friend of Shepherd's whose last name was Flickinger.
In "The Sixty-Two Curses of Caliph Arenschadd", the protagonist meets a boy who's reluctant to tell her his real name, so she dubs him 'Tumpkin' on the grounds that she has to call him something. At the end of the story, she finds out who he really is, but the reader doesn't get to learn his real name, because she keeps calling him by the name they became friends by.
In the Jackie French novel Somewhere Around the Corner, Young Jim mishears Barbara when she says her name, leading to her being known as "Bubba" to pretty much everybody in the book, despite her introducing herself as "Barbara" several times (even saying "It's Barbara, really" at one point).
Song at Dawn: Estela is not the first musician to hide behind a 'songstress's name'. Even after she's publiclly married as 'Roxane de Montburn' she still goes by 'Estela'.
Many characters in A Song of Ice and Fire have nicknames, some of which are self-styled and others less so. Peasants generally don't care about the real names of other peasants, which leads to some people being known exclusively by their nicknames, such as Lommy Greenhands, a mook named Shitmouth, and most famously Hot Pie, among others. Arya becomes this once when traveling to Braavos. She would have invented a new identity at this point, but everyone just called her "Salty", so she went with it.
In Tales of Dunk and Egg, we have the inversion of Dunk of Flea Bottom. His young squire Egg(short for Prince Aegon) asks if his name is short for Ser Duncan. Dunk briefly thinks that he's been called Dunk for so long he's not sure if it's a shorter version of his name or his true name itself. Nevertheless he decides to style himself, Ser Duncan the Tall.
"Ghost Bird" is the nickname given the biologist by her late husband and the only moniker she is known by other than "the biologist". Later, her clone refuses to be called by anything other than Ghost Bird as well.
While Control's name is actually given right away in Authority, he asks everyone to call him Control, which remains in place for the remainder of the trilogy.
Several characters in the X-Wing Series. Rogue Squadron has Hobbie Klivian, whose real name is Derek, but no one ever uses it. Wraith Squadron has the most examples — their full names are in the Dramatis Personae and usually get mentioned the first time they're introduced, but you wouldn't know that Face, Grinder, Piggy, and Runt had any other names, otherwise.
Mitth'raw'nuruodo, aka Thrawn. He went with the short version to make it easier, and it stuck. In his culture, core names are only supposed to be used by friends and family, but he doesn't seem to mind; presumably the over-familiarity is preferable to people continually mangling the pronunciation. One particular mangling comes from Vicelord Siv Kav in the form of "Mitthrawdo", no matter how many times he's corrected. Then again, Siv Kav really doesn't like Thrawn, so this is likely intentional.
Ranger in the Stephanie Plum books. His full name is Ricardo Carlos Manoso.
Swan and Sister in Swan Song; Swan's real name is Sue Wanda, but Sister doesn't actually remember her real name
In John Steinbeck's novel Sweet Thursday, a brothel keeper named Flora is known only as "Fauna".
In The Thirteenth Tale, John-the-dig's legal name is John Digence, but Vida insists that if you really knew him, you knew that John-the-dig was his real name.
In C. S. Lewis's Till We Have Faces, the princesses' Greek tutor is known only as the Fox, due to his red hair (which goes completely gray early on in the story). Only once does a character refer to him by his given name, Lysias.
Dwarves in The Lord of the Rings don't tell their names to outsiders (their real names are in the Dwarvish language, which is itself secret). Instead, they all go by use-names borrowed from the nearby humans — like "Thorin" or "Gimli".
Ents: Entish being what it is, an Ent's full name is essentially the story of their entire life, described in detail — and since Ents are The Ageless, that makes for long and rambling names. Most Ents use fragments of their name rendered into other languages for dealing with "hasty" people — i.e. "Treebeard" and "Skinbark."
In Bree, Aragorn is known exclusively as "Strider." Not that he wants his true identity shouted from the rooftops, but this nickname ain't exactly flattering. Nonetheless he adopts it (translated into High Elven as Telcontar) for his dynastic name... for some reason.
Túrin in The Silmarillion and The Children of Húrin spent his whole life fruitlessly trying to escape the curse Morgoth put on his whole family. He figured avoiding his real name would help, so every time he fled from his ruined life to go live someplace new, he introduced himself only with some unpleasant nickname he'd just made up on the spot: Neithan ("the Wronged"), Gorthol ("Dread Helm"), Agarwaen ("Bloodstained"), Wild Man of the Woods, and finally Turambar ("Master of Doom"). The Elves in Nargothrond, unsurprisingly not liking Agarwaen, nicknamed him the more flattering Adanedhel ("Elf-Man"), Thurin ("the Secret"), and Mormegil ("Black-Sword") instead. But to his eternal irritation, his real name wasn't so secret after all.
Elves are an odd case. To summarize:
Most of them have two names, a mother-name note given by their mother and a father-name note given by their father. Which name they're commonly known by appears to be a matter of personal preference.
Then, if they were given Quenya names, they Sindarinised those names, so "Tyelkormo" becomes "Celegorm", "Carnistir" becomes "Caranthir" and "Curufinwë" becomes "Curufin", to take some of the sons of Fëanor as examples.
And in some cases they choose not to be called by either their mother-name or their father-name, and take a new name that they chose for themselves or were given by someone. For example, Finarfin's only daughter decided not to be called "Artanis" (her father-name) or "Nerwen" (her mother-name), but instead called herself "Galadriel", a direct translation of "Altáriel", the name her husband Celeborn gave her.
And so, in a way, every Elf is only known by their nickname. Confused yet?
Bootsï¿½ real name is only mentioned in Gregor the Overlander, and the crawlers refer to her exclusively as "the princess".
The Orange Man in Venus Prime is never given a real name.
Arcie in Villains by Necessity, though it isn't until the last chapter that the party learns that Arcie isn't his name, it's his initials, R.C., for Reinheart Corallis MacRory.
In the Warrior Cats series, the Tribe of Rushing Water cats all have long names in a Name That Unfolds Like Lotus Blossom style, so they go by the first word of their name - "Bird Who Rides The Wind" is "Bird", for example, and "Jagged Rock Where Heron Sits" is "Jag". There are a couple Tribe of Endless Hunting ancestors named Fall and Slant that are mentioned in Sign of the Moon whose full name isn't mentioned, so even fans only know them by their nicknames.
Princess Candacis in White as Snow is almost always called Coira, a name her nurse gave her, to the point that her maids instruct a doctor to call her Coira because she won't know who he's talking to if he calls her Candacis.
''Winnie-the-Pooh': Winnie's name is a nickname for Edward Bear. For that matter, in the Disney series especially, hardly anyone ever calls him "Winnie," instead calling him "Pooh" or "Pooh Bear," and occasionally "Winnie the Pooh."
In Daniel Pinkwater's Young Adult Novel, the protagonist goes by his nom de guerre, Charles the Cat, and the other Wild Dada Ducks do likewise.
In Zen and the Art of Faking It, San falls in love with a girl named Woody, and only realizes that this isn't her real name when an adult refers to her as Emily halfway through the book.
This could also fall under Meaningful Rename since she chose the name herself and rejected the name her mother gave her. This happens again toward the end and reverses the first when she starts going by her real name again.
The Wandering Inn: The most terrifying Necromancer the world has ever seen is only known by his nickname, The Necromancer— with minor exceptions.