The excessive use of nautical slang by pirate characters ("Shiver my timbers!").
The "Black Spot" as a death sentence handed out to traitors by pirates. (Though historically this may have been done with the Ace of Spades).
In the book, Jim Hawkins, an ordinary boy, discovers a treasure map among the effects of a deceased resident at his family's inn. He shows it to two local gentlemen (a landed noble and a wealthy doctor), who charter a ship to search for the treasure on Skeleton Island, but they hire sailor-turned-tavern-owner Long John Silver as their cook, unaware that he is a pirate. Long John becomes Jim's mentor, while winning over most of the crew -who he helped hire.By chance, Jim overhears Long John's plotting, and warns his friends, just as they arrive at the island. Over the next few days, Jim repeatedly wanders into danger, meets a scary hermit and kills a pirate by himself, while Long John keeps switching sides, and the treasure is found.Jim and his friends return home rich, Long John escapes with some of the treasure, and the rest of the pirates get marooned on the island or killed.This book has been adapted into several movies, including:
Treasure Island (1920) - Silent film.
Treasure Island (1934) - Directed by Victor Fleming.
Treasure Island (1937) - A weird Soviet version.note Irish rebels led by Livesey find a treasure map and trick moneylender Trelawney into organizing an expedition. He hires pirates. Hawkins is a young woman (in love with Livesey), who dresses as a boy to join the expedition. In the end Trelawney and pirates are left on the island. The rebels needed the money to buy weapons.
Treasure Island (1950) - Walt Disney's first non-animated film. Introduced the "pirate" accent. Also got an unofficial sequel in The Return of Long John Silver.
Although originally published chapter-by-chapter in a magazine, when published as a book it became very popular, the British Prime Minister Gladstone staying up until two in the morning to finish it. It is also the ultimate inspiration for all the subsequent pirate movies and other novels, down to Pirates of The Caribbean. Many of them include a Shout-Out to Treasure Island. E.g., in Peter Pan, it is said that Captain Hook was the only man Long John Silver ever feared, while Pirates of the Caribbean: Dead Man's Chest features the "Black Spot" (in a flashier form) and the song quoted at the beginning of this entry.
Squire Trelawney in the Sky1 adaptation has Mrs Hawkins thrown out of the Admiral Benbow inn, arranges for the execution of Mr Arrow, and schemes to cheat Jim and Dr Livesy out of the treasure. In the book, while somewhat foolish, he is well-meaning and far from evil.
Also Long John in Legends Of Treasure Island is more a straight played ruthless pirate and, a fair bumbling villain role aside, lacks most of the sympathetic traits of his novel and other alternate counterparts mentioned below.
Trelawney, Smollett and even Dr. Livesey are all subjected to this in the 1999 version, to justify Long John's portrayal and Jim's decision to join him and Ben Gunn at the end.
Affably Evil: Long John, one of the ultimate exemplars of this trope. Sure, he's a lying, thieving, murdering scumbag pirate... but he's also a lovable, charismatic anti-villain! How can you hold anything against him?
Blessed Are the Cheesemakers - Ben Gunn is obsessed to the point of insanity with cheese, not having had any for three years. Dr. Livesey carries a small piece of parmesan in his snuffbox as emergency rations, and uses it to win Ben's loyalty.
Catapult Nightmare - At the very end of the book, Jim Hawkins says that the worst dreams he ever has are when he "start[s] upright in bed with the sharp voice of Captain Flint [the parrot] still ringing in my ears."
Churchgoing Villain: Silver and the other pirates, who are worried about bad luck when one of their own cuts a page from The Bible to create a Black Spot.
Even Evil Has Standards: Pirate, mutineer and murderer Long John Silver may be, but he bends over backwards, even risking the Black Spot, to keep Jim Hawkins alive, even when he stands to gain nothing by it.
Foregone Conclusion: The story is introduced as Jim's tale of his adventure, which keeps you from getting too worried whenever his life is at risk. Considering that the story already includes a boy getting hit by a thrown knife as well as being captured by pirates and threatened with torture, this may have been necessary at the time to keep the story from feeling too dark and shocking the audience.
Girls Need Role Models: The large majority of children-oriented adaptations of the novel seem to add a female co-protagonist (or gender swap an existing male one) that the original novel lacks, nearly all examples of such are almost as effective and competent protagonists (if not sometimes more so) as Jim himself. Most notable examples include Captain Amelia of Treasure Planet and Jane of The Legends Of Treasure Island. Zigzagged with Benjamina Gunn of Muppet Treasure Island (though what do you expect from a character played by Miss Piggy?).
Good Is Not Nice: Cpt. Smollett delivers a blunt assessment of his displeasure over the crew, expecting to be dismissed. Jim dislikes him from the beginning, and Trelawney comments on finding his behaviour "downright un-English," however they soon discover that he was quite right, and he leads the party's resistance for most of the story.
Handicapped Badass: Long John Silver killed an honest crewman who refused to join the pirates, by hurling his crutch at him, thus breaking his spine, and then hopping one-legged to him and slitting his throat.
Jim keeps his promise not to escape with the doctor even though his life is in danger if he stays, at the point where even the doctor himself is ready to break his word because he can't bear the thought of young Jim being tortured to death. This is the turning point in Jim's Coming-of-Age Story.
Similiarly, during Long John's final escape, he has everything to gain by shooting Jim, but he can't do it. He likes Jim too much.
Long John Silver, who gets away with his life and a few hundred pounds from the treasure (rather less than one tenth of one percent).
Also Ben Gunn. Nobody seems particularly bothered that he was a part of one of the most feared pirate crews that ever sailed, and he gets a larger share of the treasure than Silver did (which he manages to blow in three weeks, at which point he is given a pension). Presumably, the characters and readers consider his time marooned on the island punishment enough (not to mention it mellowed him out considerably). This was averted in the Sky 1 adaption, where Ben Gunn is far more sympathetic and chooses to stay on the island because he thinks the devils won't come back.
Large Ham: In most adaptations, Silver, and to a lesser extent, Trelawney.
Mundane Luxury: Ben Gunn swears Undying Loyalty to Squire Trelawney in exchange for a palm-sized piece of cheese (Parmesan, to be precise), something he has craved for years.
The Mutiny: Captain Flint's crew, under Long John Silver, rebelled in the backstory. Silver also leads the gang of pirates that rebel against Captain Smollett in the actual story.
Papa Wolf: Silver has been portrayed as this many times towards Jim. Most notably in the Disney version, in which he gave up the treasure to save Jim's life instead, and in the Sky 1 version, where he took out Squire Trelawney - who had pulled a sword on Jim - with only his crutch and while chained to the helm.
Pirate Parrot: The Trope Maker. Although it's quite likely that real Caribbean pirates may have kept the occasional parrot, this is also true of monkeys and cats, and one of these animals is far more associated with pirates than the others.
Retired Badass / Retired Monster: Flint, the captain who murdered a good chunk of his own crew to hide the treasure's location, was afraid of Silver. Silver has been peacefully running an inn and living happily with his wife for some years when the story begins.
Stiff Upper Lip: Most of the sympathetic characters. Captain Smollet maintains rigid discipline throughout their ordeal. Hawkins maintains his dignity and poise even under threat of death. The Squire's servants are said to react to every calamity without complaint or even much surprise.
What the Hell, Hero?: During a parley scene, Cpt. Smollett orders John to sit down, which John does on the condition that someone help him up after the conversation is finished. No one does, and Jim feels rather bad about this.