Achey Scars: Frodo Baggins' wounds received from the Morgul blade and Shelob often pain him afterwards and make him ill, especially on their anniversaries. He actually sails to the True West with the elves because of this, in the hope of finding a way of reducing this physical pain and the emotional scars from bearing the Ring.
Addictive Magic: The One Ring gives its user power of a sort, but at the same time creates an addiction to it, to the point where the user couldn't give it to anyone else, thus making him the only one powered by it. Only its maker Sauron is immune to this, as the "Lord of the Ring".
During the period when Sauron was thought to be dead between his defeat by the Last Alliance and his return to power, people like Isildur, Gollum and Bilbo were attracted to the Ring for its shiny beauty, but still formed a strong attachment to it. Wearing it also had the handy effect of turning them invisible (a side effect for mortals). When Sauron goes "active" again and the true nature of the Ring is revealed to the heroes, the Ring itself "awakens" also, and the potential power it bestows is extended to dominion over whole realms and races.
Frodo: It is said: 'Go not to the elves for counsel, for they will say both no and yes.' Gildor: Is that so? Elves seldom give unguarded advice, for advice is a dangerous gift, even from the wise to the wise, and all courses may run ill.
All There In The Appendices, including the love story. Tolkien's way of implying that the story of LotR, despite being one of the most important things to happen in Middle-earth, was not the only thing happening.
Arguably, from Aragorn's point of view, the whole War of the Ring is merely an Engagement Challenge.
The Appendices also makes note of fighting in the North near Erebor and acknowledges those who triumphed and died in the fighting.
All That Glitters: The phrasing is reversed—"all that is gold does not glitter"—but it fits the trope description. However it is a complete reversal of the well known phrase "not everything that glitters is gold".
All Trolls Are Different - They're 12 feet tall, turn to stone permanently when exposed to daylight, and are implied to be the result of Morgoth corrupting Ents. Then we have the Olog-hai, bred by Sauron shortly before the War of the Ring. They're similar to normal trolls in this setting, but bigger, stronger, and resistant to sunlight.
All Up To You: Quite a few times, but most notably with Sam when Frodo is captured.
All Webbed Up: Happens to Frodo after he escapes from Shelob's lair.
Alliterative Family: Happens a lot in hobbit families. The most notable example would probably be Peregrin (Pippin), son of Paladin, brother of Pearl, Pimpernel, and Pervinca.
Alternative Calendar: The different peoples have their own calendars, with varying degrees of difference between them. The books generally use the Shire (Hobbit) calendar.
Always Chaotic Evil: In one possible Back Story, orcs were magically corrupted from elf stock to be Morgoth's minions. Tolkien's own thoughts on this suggest that this may not entirely be the case, though.
Although the story required the Big Bad and his various proxies to have foot soldiers, Tolkien couldn't reconcile his own principles with the creation of even an imaginary race that was either a) soulless or b) predestined for damnation.
Ambadassador: Gandalf, ambassador from the Valar; most of the Fellowship were originally ambassadors to Rivendell. Their collected appearance prompted the Council of Elrond.
Ass in Ambassador: Between Gimli, Legolas, and Boromir, the Council is sufficiently full of this trope.
Ambition Is Evil: The One Ring corrupts by tempting the user with the power to fulfill their personal ambitions, even if those ambitions are noble at the start. Sam's only ambition is to raise a family and live quietly, so he is little affected by it, while Tom Bombadil, who is completely devoid of ambition, is completely immune to its power. Conversely Boromir, who desperately wanted to save Gondor, for love but also for glory, was easily manipulated. Faramir ardently desired peace for his people but understood that it was something the Enemy's weapon wouldn't give him, so while it affected him he didn't succumb to the temptation.
The Ring does in fact try to tempt Sam with becoming Garden-Master of the World, Ruler of All That Grows. Sam considers for a moment before realizing how profoundly silly that is.
Ancient Tomb: The Barrow-downs of the Northern Kingdom and the Dwimorberg (the haunted mountain at Dunharrow). The barrows of the Kings of Rohan and the tombs in Minas Tirith are also Ancient Tombs, but not haunted by anything.
Annoying Arrows: Played straight and then subverted; Boromir does get shot by several arrows, and does pull at least one out, but is still weakened and wounded to death and definitely cannot continue fighting.
Another Man's Terror: "We cannot get out. The end comes, and then drums, drums in the deep. I wonder what that means"
Apocalyptic Log: The Book of Mazarbul, chronicling Balin's failed attempt to retake Moria up until their last stand. It trails off at the end:
"[...] we rescued Balin's body [...] we have barred the gates but doubt if [...] can hold them long. If there is [...] no escape it will be a horrible fate to suffer [...] We cannot get out. We cannot get out. They have taken the bridge and Second Hall... fell there bravely while the rest retr [...] Mazarbul. We still ho[...]g ... but hope u[...]n[...]Óin's party went five days ago but today only four returned. The pool is up to the wall at West-gate... we cannot get out. The end comes soon. We hear drums, drums in the deep." The last line is a trailing scrawl of elf-letters: "They are coming."
Arcadian Interlude: The time spent with Tom Bombadil. The episode serves as character development for all the hobbits (especially Frodo), and to provide the hobbits with their swords, one of which becomes vitally important in the battle of the Pelennor Fields. Tom Bombadil was content with himself and thus couldn't be tempted by the Ring. Tolkien himself stated that he considered the Tom Bombadil sequence one of the most important sequences in the entire story. From a narrative perspective, he represents the mystery that remains even after a reader thinks he knows all there is to know about Middle-Earth and represents what could be lost. From a writing perspective, he gives Tolkien a chance to present backstory exposition in a way that interests the reader. Still, considered a Big Lipped Alligator Moment by some readers, which might be why it is not found in the Movie.
Arc Number: 9 - Nazgûl, Fellowship (chosen to match the Nazgûl), Rings for Mortal Men, Frodo's fingers at the end, number of people who touched the One Ring (Sauron, Isildur, Déagol, Sméagol, Bilbo, Frodo, Gandalf, Tom Bombadil, Sam).
In Real Life, an Arc Number both in Norse Mythology and popular Medieval Christianized astrology (where it represented perfection, a "trinity of trinities") - both of which influenced Tolkien immensely.
Asleep for Days: Frodo does this in Rivendell after being near-fatally wounded by the Nazgûl. It happens again to both him and Sam after getting rescued from Mount Doom, due to their near starving, wounded state.
Author Avatar: Faramir, whom Tolkien considered himself to be most like out of all the characters. An early version of him explained in depth about the Elves.
Authority Equals Asskicking: Théoden is King of Rohan and pretty handy with a sword as well, Aragorn is Chieftain of the Dúnedain and King of Gondor and hacks his way through a whole mess of orcs and Uruk-hai.
Gil-Galad. Last High King of the Elves, was described as an unmatched fighter/leader and died taking Sauron with him (who may have been barely weaker than Morgoth at the time).
Babies Ever After: Sam marries his longtime sweetheart the year after the end of War, and the next year sees the birth of little Elanor. He goes on to have twelve more, although, as the epilogue was cut, this is revealed in the Appendices instead of in the narrative.
Badass Boast: See the Literature sub-page of that trope for numerous examples.
Éowyn's is probably the most famous.
Frodo's to the Nazgûl at the ford.
Gandalf leaving cautionary signs to the enemy that read as "Gandalf is here" all over the place, reciting his credentials while stonewalling the Balrog in Moria, and later reassuring Gimli by telling him:
Bearer of Bad News: Gandalf has quite a reputation for this in many places. The Rohirrim don't like him much because of it — they call him Stormcrow.
Of course, as Gandalf himself points out, he has this reputation because he tends to seek out the places where his help is most needed.
Because Destiny Says So: "There are other forces at work besides the will of evil... Bilbo was meant to find the Ring, and not by its maker."
Although considering this is Tolkien we're talking about, he probably intended it to be more "because Eru says so."
Being Watched: Being eavesdropped on by Sam (for the most heart-warming conspiracy ever) and several times with Gollum. Also, there are several moments when the good guys either perceive directly the gaze of the Eye of Sauron, or feel themselves watched from above by the winged Nazgûl.
Benevolent Boss: Bilbo Baggins to Hamfast Gamgee, his gardener, and in turn, Frodo to Sam.
Berserk Button: You'd think the Ents are as angry as they could possibly get, considering all that Saruman's done to their forests - and then he gets his machinery going when they're attacking Isengard. Several of them get badly burned and one of them, Beechbone, is sprayed with liquid fire and burns 'like a torch', which presumably kills him. They then proceed to get really mad.
Gimli gets angry if you diss Galadriel.
Trying to hurt Frodo in front of Sam is a mistake you won't live to regret...because you won't live much longer.
Best Friends In Law: Sam and Pippin, thanks to the marriage of Goldilocks Gamgee to Faramir Took.
Better than a Bare Bulb: Many examples, done very well, of characters noting they are like, or are, characters in a saga and that some trope applies to them. "Give us a story, I want to hear about 'Frodo of the Nine Fingers and the Ring of Doom'", et cetera.
Better to Die than Be Killed: Denethor. Of note is that this is presented as an utterly reprehensible decision — it comes closer than anything in the book to actually being called a sin. Tolkien deliberately has Gandalf use the anachronistic term "heathen" in his final dressing-down of Denethor. Of course, this may have less to do with him trying to kill himself and more to do with him trying to take Faramir with him.
Big Bad Duumvirate: Subverted. Saruman seems to consider himself Sauron's equal partner and has full plans of double-crossing him, but Sauron is both phenomenally more powerful and smart enough to be fully aware of his pawn's ambitions. It's quite clear to everybody else that there is only oneBig Bad in Lord of the Rings.
Bigger Bad: Morgoth. Sauron is merely his lieutenant: he was exiled from the world (but not destroyed) long before the War of the Ring.
Big Damn Heroes: Several times— Gandalf at Helm's deep, the Rohan army at Pelennor and later Aragorn, Legolas, Gimli, the Grey Company and a host of men from south Gondor in the same battle.
Big Eater: Pretty much the entire Hobbit race. Six meals a day is considered normal for them, and many young Hobbits learn to cook before they learn to read (if ever). This trope is taken Up to Eleventy-one when it comes to special occasions like Bilbo's 111th birthday party...
Big Good: Gandalf. Galadriel and Elrond to some extent as well.
There are at least two tiers of even Bigger Goods, but they remain entirely offscreen.
Blood-Stained Letter: The account of the failed attempt to recolonise Khazad-Dum, discovered by Gandalf and the Fellowship when navigating through Moria, is explicitly described as hacked, chopped, partially burnt and smeared with long-spilt dried blood. Especially on the final page, carrying only the scrawled runes "They Are Coming!"
Blunt Yes: It isn't quite as explicit in the Book as it is in the Movie, but Denethor admits he wished Faramir died in his brother's stead (the discussion is superficially about which brother should have been in Ithilien, but the message is still clear):
‘Do you wish then,’ said Faramir, ‘that our places had been exchanged?’
Body Motifs: A subtle theme throughout the book is that good guys tend to be gifted with better sight and/or hearing; clean, human senses. Bad guys, meanwhile, have much better smell, which lends them an animalistic or Uncanny Valley feel. Sauron is an exception, although the eye that he uses as his symbol still is uncanny, being 'a great eye, lidless, and wreathed in flame'. On the other hand, Frodo finds that his sight (in the dark) and hearing are improved after he has been stabbed with the Morgul blade, an evil weapon.
Breaking Lecture: Saruman harangues all of his triumphant enemies, and all are swayed by the power of his voice; likewise, the Riders of Rohan (except for Théoden, as it happens) are wholly overcome by it, while Pippin is particularly shamed. Gandalf breaks the effect by laughing.
Early in the quest Gandalf is incredibly pleased to hear from Butterbur that the Hobbits have left with Aragorn, and shouts "May your beer be under an enchantment of surpassing excellence for seven years!" At the very end of the book the Hobbits find that while everything else has gone to hell in their absence, Butterbur's beer is better then ever.
In The Hobbit, Lobelia Sackville-Baggins was caught trying to take the silverware from Bag End when Bilbo returned from Erebor and he had been declared Legally Dead. After the Party, Bilbo's semi-comedic will states the Sackville-Baggins are to receive his spoons. Lobelia is not amused.
She took the spoons, though.
When Frodo and his companions arrive at the inn in Bree, they realize they're going to need a plausible explanation for their wandering out of the Shire — so Frodo claims to be a historian who's thinking of writing a book about the relationship between the Shire and Bree. Two volumes later, as they're returning home through Bree, Frodo is asked if he's written his book yet. He says he's still getting his notes in order.
But Now I Must Go: The passing of the Three rings and their bearers. This is played most straightly with Gandalf, who was meant to serve as a paragon in Middle-Earth.
Call a Rabbit a "Smeerp": Pipe-weed (tobacco), Oliphaunts/Mûmakil (large elephants). Though oliphaunt is an archaic English usage, so not literally Smeerp territory.
Call Back: The Battle of the Black Gates has one to The Hobbit, with Pippin hearing the shout of "The Eagles! The Eagles are coming!" In a parallel with the Battle of the Five Armies as well, Pippin is knocked unconscious immediately after hearing it, as Bilbo was just after saying it. He doesn't even believe that he actually heard the cry, since he thinks 'That came in his [Bilbo's] tale, long long ago.'
The Call Knows Where You Live: Frodo never actively resists the Call, but (as he doesn't just jump and run unprepared, but instead makes and executes a careful plan for his disappearance and subsequent journey) he just avoids meeting a Nazgûl literally on his front doorstep; it's his neighbor, Ham Gamgee (Sam's father), who tells the Black Rider that Frodo has gone away — and doesn't quite tell him precisely where Frodo has gone.
Cannot Cross Running Water: When the Ringwraiths attempt to pursue Frodo across the river Bruinen toward Rivendell, the waters rise up and overcome them at the command of Elrond, with a little help from Gandalf. It is also noted that the Ringwraiths seem reluctant to enter the water until Frodo provokes them. This seems to be a call back to an earlier draft where the Nazgûl were afraid to enter water, an idea that Tolkien ultimately abandoned due to the existence of multiple river crossings between Mordor and the Shire. The earlier thwarting of the Nazgûl at the Brandywine is justified by the depth of the river, forcing the Ringwraiths to go north ten miles to cross the bridge there.
There is a moment where Frodo and Sam pass by Shelob's actual lair and can feel or see nothing but the stench of her lair, which is suggested to be even blacker than the pitch black around it, as if inhabited by the actual absence of light. A very effective case of Nothing Is Scarier, since you don't know if she's home or not.
The Cavalry: The Riders of Rohan and Aragorn, Rangers of Eriador and troops from southern Gondor. They are also, literally, the cavalry. On the evil side, the Haradrim.
Cavalry Betrayal: Inverted. The fleet of ships of the Corsairs of Umbar, allies of Sauron, arrive at the Battle of the Pelennor Fields to the rejoicing of his armies... only Aragorn had intercepted and captured it, and the ships are flying the royal colours and filled with soldiers from southern Gondor.
Cerebus Syndrome: discussed by the author Tolkien himself in his Letters. The book started out as a shorter sequel to The Hobbit and the earlier chapters display much of the whimsy of the latter. Gandalf's personality also gets Darker and Edgier as time goes on. Less surprising when recalling that the Hobbit's story was moved to Middle-earth, and its previously existing tales had already been even darker.
Character Title: "The Lord of the Rings" is none other than Sauron, the main antagonist. "The Fellowship of the Ring" refers to the nine protagonists in the Fellowship, and "The Return of the King" to Aragorn.
Chekhov's Gun: Galadriel's gifts to the Fellowship and the elven rope from Lórien play useful parts later. The Númenórean barrow-blade given to Merry proves vital in defeating the Witch-King, plus the One Ring itself is a retroactive Chekhov's Gun from The Hobbit.
Chekhov's Boomerang: Frodo's mithril shirt, given to him by Bilbo. It saves his life in Moria. Later it comes in handy when it incites the Orcs to fight over it. It proves helpful yet again when it foils Saruman's attempt to stab Frodo.
Chessmaster: Sauron, Saruman, Gandalf and Denethor are the main ones. They actually see their power game as such explicitly in the Book. Denethor's "he uses others as his weapons" is probably the main doctrine of Chessmastery.
Chess Motifs: Pippin refers to himself as a pawn, but "on the wrong chessboard."
The Chew Toy: Poor Arvedui, the last king of Arnor, couldn't catch a break. His parents named him "Last King" because a seer told them he'd be last. He inherited Arthedain when it was little more than a rump state reduced by wars against Angmar, and his claim to kingship of Gondor (through marriage to the daughter of King Ondoher) was rejected because only male inheritance was valid in Gondor, Arthedain was not nearly powerful enough to lay claim to Gondor, and Arvedui himself was Overshadowed by Awesome, namely by the victorious general Earnil who was related distantly to Ondoher. Then Angmar invaded Arthedain again, overran Fornost, and Gondor comes too late to help. Arvedui fled north to take a ship to Lindon, but the ship crashed and he drowned, taking the palantíri of Annúminas and Amon Sûl with him.
The Chosen One: Frodo (and Bilbo) were meant to have the Ring. Also, Aragorn is Isildur's heir.
Chronoscope: The Mirror of Galadriel can show visions of the past and the future. Sam sees events that will occur in The Two Towers during his and Frodo's entry into Mordor, as well as events in the Shire after Saruman takes over. Frodo sees the fall of Númenor and the founding of Gondor, which occurred in the distant past.
Chuck Cunningham Syndrome: The wizard Radagast the Brown disappears and is simply never mentioned again after the Council of Elrond. And to carry the trope even further, the backstory says that five Istari came to Middle-Earth, but the two Blue Wizards promptly went off into the East and don't appear in the story at all.
Citadel City: Minas Tirith being one of the codifying examples. Minas Morgul as well.
Color-Coded Wizardry: Saruman the White, Gandalf the Grey, Radagast the Brown. There's also the Blue Wizards, Alatar and Pallando, but they do not appear in any stories; we're told that they went far into the east and were never seen in the West of Middle-earth again, and no-one there knows precisely what they got up to.
Come with Me If You Want to Live: Aragorn gets introduced this way in Bree, albeit in a particularly slow-moving fashion. While it's implied the hobbits would have been quickly ambushed in their beds without him, they do spend some time gathering supplies prior to departure (though a great deal of that is due to the hobbits' ponies having fled, denying them a quick exit and forcing them to procure another—Bill—to carry their excess supplies). This is more pronounced in the film, however.
Compressed Hair: Played straight when Éowyn reveals her presence on the battlefield by removing her helmet and unloosing her hair. In an early draft, though, Tolkien averted the trope by noting that Éowyn had cut her long hair short before donning armor.
Confusing Multiple Negatives: As part of the build-up to his "joke" with the Ring, Bilbo drops into his birthday speech the amusing line "I don't know half of you as well as I should like—and I like less than half of you half as well as you deserve!" This sends the party into a moment of confusion, including a widespread counting of fingers, to see if that's actually a compliment....
Constantly Curious: Pippin during the ride with Gandalf to Minas Tirith. Gandalf tries answering questions, but finds each answer just leads to more questions; they wind up joking together about Pippin's curiosity. Exposition nicely done.
Constructed World: Set in the world of Tolkien's legendarium, on the continent Middle-earth.
Contemptible Cover / Art Shift: In the first authorised American paperback, Tolkien complained about the creative artwork◊ for the covers. "Horrible colours and foul lettering." The Hobbit featured the part of this work showing a "tree with bulbous fruit" and "lions and emus" on the covers◊. The editors' representative called Tolkien up to explain that Remington hadn't had time to read the book and that the ornaments on the tree were "meant to suggest a Christmas tree". Tolkien said (in somewhat more colourful language) that he felt like the Only Sane Man. The Ballantine edition, with its expressionistic covers, is nicknamed the "Hippie Edition". (Interview with Remington here.)
Contralto of Danger: Galadriel speaks in a deep contralto in the book, and she's often described by lesser mortals as incomprehensible and dangerous (which isn't surprising considering she hails from an age when her kin were the main source of trouble in the Middle Earth).
Contrived Coincidence: Gollum just so happens to have found his way into Moria, and is lurking there at the exact same time the Fellowship pass through. There are a few other instances, supporting Gandalf's belief that a hidden hand is opposing Sauron very, very subtly.
Cool Chair: The throne of the King of Gondor, and the Steward's chair.
Cool Sword: Gandalf has Glamdring, Frodo has Sting, and Aragorn has Andúril. The Witch-King of Angmar wields a flaming sword at the Siege of Gondor, and the Balrog of Moria uses a burning sword as well.
Corpse Land: The Dead Marshes, a foul bog stretching for miles filled with corpses from the first war with Sauron. Spirits of the men, elves, and orcs that were buried there try to lure travelers into the marshes to add to the body count.
The Corruptible: Boromir was the one in the Fellowship most open to the seduction of the Ring.
Without Isildur's fall to the corruption of the Ring, it would not have survived Sauron's fall. The race of Men in general are often seen as easily corrupted.
Gandalf: Far, far down below the deepest delvings of the dwarves, the earth is gnawed by nameless things. Even Sauron knows them not. They are older than he.
The Balrog tries to run off and leave him there, and chasing after him becomes Gandalf's hope of finding a way out.
Cosmopolitan Council: The Council of Elrond. Possibly also The White Council — which we know included Gandalf, Saruman, Galadriel and Celeborn, and Elrond.
Counterspell: While the Fellowship is in Moria being pursued by orcs (and worse), Gandalf stays behind to hold a door closed. The opposition breaks through anyway, but the door's destruction also causes a cave-in, blocking the passage behind. A few moments later Gandalf tells the rest of the Fellowship what happened.
I could think of nothing to do but to try and put a shutting-spell on the door. [...] Then something came into the chamber [...] and then it perceived me and my spell. What it was I cannot guess, but I have never felt such a challenge. The counter-spell was terrible. It nearly broke me. For an instant the door left my control and began to open! I had to speak a word of Command. That proved too great a strain. The door burst in pieces.
Gandalf sometimes cultivates this image, such as when he pretends to be a harmless old man at Meduseld. Hama the doorwarden isn't fooled — "A staff in the hands of a wizard may be more than a prop for age" — but he still trusts in Gandalf's essential goodness.
Cruel Mercy: This is how Saruman views Frodo's decision in the Scouring of the Shire.