The Lexicon

101 words and phrases from the tabletop, the screen and the page, each with where and when it came from.

Letter

Used in

Ability scores also attributes, stats, 3d6 in order: Numbers rating a character's basic capacities. D&D's six (Strength, Intelligence, Wisdom, Dexterity, Constitution and Charisma), originally rolled on three six-sided dice each, became the template for countless games, from Ultima to Baldur's Gate 3.; Dungeons & Dragons (1974).
Active Time Battle also ATB: Square's hybrid combat system in which each character's gauge fills in real time, and the player must choose actions as turns come up while enemies keep acting. It added urgency to menu-based JRPG battles.; Designed by Hiroyuki Ito, reportedly inspired by watching cars of different speeds pass one another in a Formula One race; introduced in Final Fantasy IV (1991).
Adventure module also module, adventure, scenario: A prewritten adventure published for game masters to run: maps, room keys, monsters, treasure and a hook to get the party moving. Classic modules such as The Keep on the Borderlands and Tomb of Horrors taught a generation how to design dungeons.; Dave Arneson's The Temple of the Frog, in the Blackmoor supplement (1975), is usually counted as the first published adventure; TSR's standalone module line began in 1978.
Aggro also threat, hate: Short for aggravation or aggression: an enemy's hostile attention. Online RPGs track which player each monster most wants to attack, and managing aggro, keeping it on the tank and off the healer, is central to group play. Pulling too much aggro is the classic way to start a wipe.
Alignment: A character's moral and ethical outlook, expressed on D&D's grid of Law versus Chaos and Good versus Evil, from Lawful Good to Chaotic Evil. Endlessly debated at the table, the nine-box chart later became a popular internet meme applied to everything from sitcom characters to sandwiches.; Original D&D (1974) offered Law, Neutrality and Chaos, drawn from Poul Anderson and Michael Moorcock; Gygax added the Good–Evil axis in The Strategic Review in 1976, and AD&D made the nine alignments standard.
Armor Class also AC: A rating of how hard a target is to hit, combining armor, shield and agility into one number. In early D&D lower was better (plate and shield was AC 2), which made attack math notoriously confusing; third edition (2000) flipped it so that higher is better.; Credited to Dave Arneson; the idea may have been inspired by the naval wargame Don't Give Up the Ship!, though no attribute of that name appears in its published rules. It entered print with Dungeons & Dragons in 1974.
Bleed: Emotional spillover between player and character: feelings from the game carried into real life, or real feelings shaping play. Bleed can be powerful and deliberate, especially in Nordic larp, but it is also a reason for Safety tools.; Named by designer and scholar Emily Care Boss; developed in Nordic larp discourse.
Blobber: A first-person dungeon crawler in which the whole party moves around the grid as a single unit, or blob. Wizardry, The Bard's Tale, Might and Magic and Dungeon Master are classic blobbers; Legend of Grimrock and Etrian Odyssey kept the form alive.
Boffer also foam weapon, padded weapon: A padded foam weapon used for safe, full-contact combat in live-action games. American battle games such as Dagorhir and Amtgard built whole combat systems on boffers, with hits counted by body location.
Boss also boss fight, boss battle: An especially powerful enemy that caps a level, dungeon or story arc. Boss fights test everything the player has learned and are often the most memorable moments in a game.; The PLATO game dnd (1975) is credited with the first video game boss, guarding an orb at the bottom of its dungeon.
Buff & debuff also buff, debuff: A buff is a temporary effect that strengthens a character; a debuff weakens one. As a verb, buff (and its opposite, Nerf) also describes developers strengthening or weakening something in a balance patch.
Campaign setting also setting, campaign world: A fictional world packaged for play, with maps, histories, gods and factions that a group can adventure in over many sessions. Published settings such as Greyhawk, the Forgotten Realms and Eberron became franchises that spawned novels and video games.; Home campaigns such as Blackmoor and Greyhawk came first; TSR published the World of Greyhawk folio in 1980.
Character class also class: A package of abilities that defines what a character does, such as fighter, wizard, cleric or thief. Classes make roles distinct and parties interdependent, and they became a backbone of computer and online RPGs, from Wizardry to World of Warcraft.; Dungeons & Dragons (1974) introduced three classes: Fighting-Man, Magic-User and Cleric. The Greyhawk supplement (1975) added the Thief.
Conlang also constructed language: A language invented deliberately, with its own sounds, grammar and vocabulary, rather than evolved naturally. Tolkien built Middle-earth partly as a home for his Elvish languages; later fantasy and games have commissioned conlangs for extra depth.
Cooldown: A waiting period after using an ability before it can be used again. Cooldowns replaced or supplemented Mana as the main limit on powers in MMORPGs and action games, turning combat into a rhythm of rotations.
Cosplay: Dressing as a specific character from fiction, games, comics or anime, often with elaborate handmade costumes and performance. A fixture of Gen Con, Dragon Con and every major fan gathering.; The Japanese word kosupure, from costume play, was coined by Nobuyuki Takahashi in 1983; fan costuming itself dates to the first World Science Fiction Convention in 1939.
Critical hit also crit, natural 20, nat 20, fumble: An exceptional success, typically a natural 20 on the d20, that deals extra damage or produces a spectacular result; its opposite, the fumble or natural 1, is a comic disaster. Crits are among the most celebrated moments in Actual Play shows.; From wargames and early roleplaying; in video games, Dragon Quest (1986) used a fixed critical-hit chance of 1 in 64.
Crunch and fluff also crunch, fluff: Gamer shorthand for a book's two kinds of content: crunch is rules and statistics, fluff is setting, story and atmosphere. A crunchy game has heavy, detailed mechanics.
Dragon kill points also DKP: A points system raiding guilds use to share scarce boss loot fairly: members earn points for attendance and spend them to bid on items. It turned guilds into small economies with their own bookkeeping.; Devised in 1999 by a player called Thott for the EverQuest guild Afterlife, named for the dragons Lady Vox and Lord Nagafen.
Dungeon crawl: An adventure in which characters explore a confined labyrinth of rooms and corridors, fighting monsters, avoiding traps, solving puzzles and hauling out treasure. It is the oldest scenario in roleplaying and the template for countless board and video games, from Dungeon! to Diablo.; The underground expeditions of Dave Arneson's Blackmoor campaign (early 1970s), published with Dungeons & Dragons (1974).
Eucatastrophe: The sudden, joyous turn in a story when all seems lost, such as the eagles' arrival or the Ring's destruction. Tolkien considered it the highest function of fairy-story: a glimpse of joy beyond the walls of the world.; Coined by J. R. R. Tolkien, from the Greek eu (good) plus catastrophe, in On Fairy-Stories, based on a 1939 lecture.
Experience points also XP, EXP: Points awarded for defeating foes, finding treasure or achieving goals, which accumulate until a character gains a level and becomes more powerful. In original D&D much of a character's experience came from treasure recovered, rewarding cunning over combat; later games shifted rewards toward fights, quests and story milestones.; Introduced by Gygax and Arneson in Dungeons & Dragons (1974), building on the level-up system Arneson used in his Chainmail-based games.
Fantasy heartbreaker: A lovingly made independent fantasy RPG that contains genuinely good ideas but is so close to D&D in its assumptions that it has little chance of finding an audience. The phrase is affectionate and rueful at once.; Coined by designer Ron Edwards in an essay for The Forge in the early 2000s.
Fix-up: A novel stitched together from previously published short stories, revised to connect them. Many fantasy and science-fiction books of the pulp and paperback eras began this way.; Coined by science-fiction writer A. E. van Vogt, who published several fix-ups of his own.
Fudging: When a Game Master secretly alters a die roll or a monster's statistics, usually to spare the party or keep the story on course. Whether it is kindness or cheating is one of the hobby's oldest arguments.
Gacha: A monetization mechanic, named after Japanese capsule-toy vending machines, in which players spend currency on random draws for characters or items. It became central to Japanese mobile RPGs in the early 2010s; Japan banned the complete gacha variant in 2012.; From gashapon capsule-toy machines; widely adopted in Japanese mobile games from the early 2010s.
Game Master also GM, Dungeon Master, DM, referee, Storyteller, Keeper: The player who runs the game: describing the world, voicing every Non-player character, adjudicating rules and deciding what the dice mean. Different games give the role different names, such as Dungeon Master in D&D, Storyteller in Vampire: The Masquerade and Keeper in Call of Cthulhu. The role descends from the neutral umpire of refereed wargames.; Early D&D called the role the referee; the term Dungeon Master soon became D&D's own, and Game Master became the generic term across the hobby.
GM screen also Dungeon Master's screen, referee screen: A folding cardboard screen that hides the Game Master's maps and dice from the players while printing the most-used tables on the inside. It is both a practical tool and a symbol of the referee's secret knowledge.; TSR's Dungeon Masters Screen, printed with the most frequently used charts from AD&D, appeared alongside the 1979 Dungeon Masters Guide.
GNS theory also Gamism, Narrativism, Simulationism: Ron Edwards's model of roleplaying that sorts players' priorities into Gamism (overcoming challenges), Narrativism (creating meaningful story) and Simulationism (exploring a consistent world). Controversial and much revised, it shaped a wave of indie story games.; First set out in Edwards's essay System Does Matter, posted in July 1999, and developed on The Forge forums.
Gold farming: Playing an online game to collect in-game currency for sale to other players for real money. It became an industry in the 2000s, often in workshops employing low-paid players, and game operators generally ban it.
Griefing also griefer: Deliberately harassing other players in ways the game does not intend, such as killing newcomers, stealing kills, blocking doorways or destroying player-built structures, for the pleasure of causing grief.; Applied to online games by the late 1990s, notably in Ultima Online communities.
Grinding also farming: Repeating the same fights or tasks to accumulate Experience points, gold or items. Sometimes a design choice and sometimes a flaw, grinding was notorious in early JRPGs and MMORPGs, and it gave rise to paid services and Gold farming.
Grognard: A veteran gamer devoted to older games and styles, often wargames or early editions of D&D, and skeptical of newer ones. Used with both affection and exasperation.; From the French for grumbler, the nickname of Napoleon's veteran soldiers of the Old Guard; adopted by wargamers and later by roleplayers.
Gygaxian naturalism: The habit, seen in Gary Gygax's early rulebooks, of treating monsters as parts of a functioning ecology, with lairs, young, diets and numbers appearing, rather than as isolated combat encounters. The phrase is used approvingly by old-school players who like dungeons that feel like places.; A label applied later by old-school fans and bloggers, not a term Gygax used himself.
Hard & soft magic systems also magic system, hard magic, soft magic: A hard magic system follows explicit rules and costs that readers understand, so characters can solve problems with it; soft magic stays mysterious and wondrous, like Gandalf's. Games need hard systems, which is why every RPG turns magic into rules and resources.; Popularized by Brandon Sanderson's 2007 essay on what he called Sanderson's First Law of magic.
Hexcrawl: A wilderness adventure played on a map divided into hexagons, each holding terrain and perhaps a lair, ruin, village or dungeon. Players choose where to travel and the referee reveals what they find, making exploration itself the adventure.; Original D&D's wilderness rules (1974) suggested Avalon Hill's Outdoor Survival board for overland travel; the term hexcrawl is a later coinage popular in the Old-School Renaissance.
Hit points also HP, health: A number measuring how much damage a character or creature can take before it is defeated. Attacks subtract hit points and rest or healing restores them, turning the drama of a fight into a steadily falling total. Nearly every Western Computer RPGs (CRPG) and Japanese RPGs (JRPG) inherited the idea, usually as a shrinking health bar.; Coined by Dave Arneson while adapting Chainmail's one-hit-kills into longer fights for single heroes in his Blackmoor campaign; codified in Dungeons & Dragons (1974).
Homebrew: Rules, monsters, classes, settings or adventures made by players themselves rather than bought from a publisher. Homebrew is as old as the hobby, since early D&D practically required referees to invent, and today it thrives on platforms such as D&D Beyond and in communities built around open licenses.
Initiative: The procedure that decides who acts first in combat and in what order, usually by rolling dice and adding a speed bonus. Rolling initiative is the signal that a scene has turned into a fight.
Instanced dungeon also instance, instancing: A copy of a dungeon or zone created separately for one group, so parties do not compete for the same monsters in a shared world. Instancing solved the problem of thousands of heroes all wanting to slay the same dragon.; When instancing first appeared is uncertain; The Realm Online (1996) is sometimes credited, and Anarchy Online and World of Warcraft made it standard.
Invincibility frames also i-frames: A brief window, measured in animation frames, during which a character cannot be hurt, typically while dodging or rolling. Mastering the dodge-roll's i-frames is central to Soulslike combat.
Isekai: Japanese for another world: stories in which someone from our world is transported, reincarnated or summoned into a fantasy realm, often gaining special powers. A close cousin of Portal Fantasy, it dominates much of modern light novels and anime and overlaps with LitRPG & Progression Fantasy.; Rooted in folktales such as Urashima Taro; modern examples date from the late 1970s and 1980s, and the genre boomed in the 2010s alongside Sword Art Online.
Kiting: Leading an enemy around while attacking it from range, staying just out of its reach, like a kite on a string. A staple tactic of ranged characters in MMORPGs and action RPGs.
Legacy game: A board game that changes permanently as it is played, as players tear up cards, place stickers on the board and open sealed boxes, so that each copy tells its own campaign story. Gloomhaven brought legacy elements to the dungeon crawl.; Pioneered by designer Rob Daviau with Risk Legacy (2011).
Level up also leveling, ding: Gaining a level once enough Experience points accumulate, improving a character's abilities in a single jump. The satisfying moment of leveling up, inherited from D&D, is one of the most widely copied mechanics in all of gaming.; Dungeons & Dragons (1974), from Dave Arneson's earlier Chainmail-based campaigns.
Living campaign also shared campaign, organized play: An organized-play format in which thousands of players run characters through a shared, persistent setting at conventions and game stores, with results carried from table to table. The RPGA's Living City and later Pathfinder Society and D&D Adventurers League followed this model.; Developed by TSR's Role Playing Game Association (RPGA), which ran large programs at Gen Con from the 1980s.
Loot & loot tables also drops, treasure tables: The treasure taken from defeated foes and explored rooms. A loot table is the list of possible rewards and their odds, a mechanism born in the random treasure tables of early D&D and perfected by Diablo's color-coded item drops.
Loot box also loot crate: A purchasable virtual container that yields random items. Loot boxes drew regulators' attention in several countries because of their resemblance to gambling.
Ludonarrative dissonance: A conflict between what a game's story says and what its gameplay makes the player do, such as a gentle hero who must kill hundreds of enemies. The term is a portmanteau of ludology and narrative.; Coined by designer Clint Hocking in a 2007 blog post about BioShock.
Mana also MP, magic points: A pool of magical energy spent to cast spells and replenished by rest or potions, usually shown as a blue bar. It is the chief alternative to Vancian magic and made famous in card games by Magic: The Gathering's lands.; From a Polynesian and Melanesian word for spiritual power, described to Western readers by R. H. Codrington in The Melanesians (1891); Larry Niven's 1969 story Not Long Before the End imagined mana as a finite, exhaustible resource.
Meeple: A small, flat, human-shaped wooden playing piece, now the unofficial mascot of hobby board gaming. The word is a contraction of my people.; Coined by American gamer Alison Hansel in November 2000 while playing Carcassonne (2000), which popularized the piece's modern shape.
Metagaming: Using out-of-character knowledge, such as a monster's statistics from the rulebook or what another player overheard, to guide a character who could not know it. In competitive games the metagame also means the prevailing strategies players expect from each other.
Min-maxing also powergaming, optimization: Building a character to maximize strengths and minimize whatever the rules let you neglect, sometimes to absurd effect. Admired as system mastery by some players and derided as munchkinism by others, it applies equally to tabletop builds and online games.
Mob also mobile, mobile object: A computer-controlled creature in an online game, especially a hostile one to be fought. Players talk of pulling, killing and farming mobs.; From mobile object, Richard Bartle's term for self-moving objects in MUD1 (1978); DikuMUD's code later shortened mobile to mob, and the usage passed to EverQuest and beyond.
Monomyth also hero's journey: Joseph Campbell's pattern of the hero who leaves home, passes trials, wins a decisive victory and returns transformed. Folklorists criticize it as oversimplified, but it deeply influenced screenwriting and fantasy storytelling.; Set out in Campbell's The Hero with a Thousand Faces (1949); he borrowed the word from James Joyce's Finnegans Wake (1939).
Monty Haul: A campaign in which the Game Master hands out treasure, magic items and experience far too generously, until the characters become absurdly powerful. The name puns on Monty Hall, host of the game show Let's Make a Deal.; Slang from the early years of D&D.
Moral panic: A wave of public fear in which a group or activity is cast as a threat to society, with the danger exaggerated by media and campaigners. Fantasy games have been targets repeatedly, above all in the Satanic Panic of the 1980s.; Developed by sociologist Stanley Cohen in Folk Devils and Moral Panics (1972).
Multiclassing also dual-classing: Combining the abilities of more than one Character class in a single character. Early D&D reserved true multiclassing for demihumans such as elves and dwarves and allowed humans only a restrictive dual-class option; later editions opened it to all.
Murderhobo: Joking description of adventurers as rootless wanderers who kill everything they meet and loot the bodies. It captures, and mocks, the default morality of the classic Dungeon crawl.; Online gamer slang, widespread by the 2010s.
MUSH also Multi-User Shared Hallucination: A text-based online world, descended from MUDs, focused on social play, collaborative storytelling and user-built content rather than combat. MUSHes hosted long-running roleplaying communities set in both original worlds and licensed fictions.; TinyMUSH grew from enhancements to TinyMUD (1989), whose social, build-your-own design it inherited.
Mythopoeia also mythopoesis, mythopoeic: The deliberate creation of a mythology within fiction: invented gods, cosmologies and legends that feel ancient. Tolkien's legendarium is the defining example, and the Mythopoeic Society took its name from the idea.; From Greek for myth-making; Tolkien used Mythopoeia as the title of a poem written in 1931 for C. S. Lewis.
Nerf: To weaken an item, ability or character in a game update, usually for balance; the opposite of a buff. Players protest nerfs to their favorite builds as loudly as any policy change.; From the Nerf brand of soft foam toys, which are designed to be harmless.
Non-player character also NPC: Any character not controlled by a player: the innkeeper, the villain, the hireling and the king, all voiced by the Game Master. The term passed into video games for computer-controlled characters and, much later, into internet slang as an insult (see NPC (meme)).
NPC (meme) also NPC Wojak: Internet slang, drawn from the gaming term Non-player character, for people accused of not thinking for themselves and repeating stock phrases like a scripted game character. The gray-faced NPC Wojak image became a political insult and later a TikTok performance trend.; The NPC Wojak appeared on 4chan in 2016; it drew mainstream press coverage in October 2018, and NPC streaming went viral on TikTok in 2022.
One-shot: A self-contained adventure designed to be played in a single session, common at conventions, for trying new systems and in Actual Play specials. Critical Role itself began as a birthday one-shot.
Permadeath also permanent death: A rule under which a dead character is gone for good, with no reloading from a save. It is a defining trait of the Roguelikes, a feature of hardcore modes in games such as Diablo II, and a permanent risk for units in tactical games like Fire Emblem.; Rogue (1980) deleted its save file when the character died, a design copied by its descendants.
Planetary romance also sword and planet: Adventure fiction set on an exotic alien world, where swords, beasts and princesses mingle with strange science. Edgar Rice Burroughs's Mars books defined it, and Appendix N's list shows how much it shaped early D&D.; Edgar Rice Burroughs's first Barsoom story, serialized in 1912, set the template.
Player character also PC: A character controlled by one of the players rather than by the Game Master. The shift from commanding armies to embodying a single persistent hero, who remembers, grows and can die, is what separated the roleplaying game from the wargame.; The persistent individual character emerged in Dave Arneson's Blackmoor campaign (1971) and was published in Dungeons & Dragons (1974).
Player killer (PK) also PK, PKer, PvP: A player who attacks and kills other players' characters, especially where the game allows it but most people would rather not. Unrestricted player killing in Ultima Online (1997) sparked years of design debate, reputation systems and separate PvP servers.
Polyhedral dice also the d20, d4, d6, d8, d10, d12, d20: The set of four-, six-, eight-, ten-, twelve- and twenty-sided dice used by roleplaying games, written in shorthand such as 3d6 (three six-siders added together) or d20. The icosahedral d20 became the emblem of D&D and gave its name to the d20 System of 2000.; Wargamers began using non-cubical dice around the end of the 1960s; Dungeons & Dragons (1974) made them standard equipment.
Powered by the Apocalypse also PbtA: A family of games built on the design of Apocalypse World, in which players trigger moves by describing fictional actions and roll 2d6, where 10+ is a success, 7–9 a success with a cost and 6 or less lets the GM make a move. Dungeon World and Masks are well-known examples.; Developed by Vincent and Meguey Baker for Apocalypse World (2010).
Procedural generation also procgen, random generation: Creating game content such as dungeons, maps, loot or entire histories with algorithms rather than by hand, so each play-through differs. It descends from the random dungeon and treasure tables of early D&D.; Rogue (1980) generated a fresh dungeon each game; later milestones include Diablo's randomized levels (1996) and the simulated world histories of Dwarf Fortress (2006).
Raid: A large-group challenge in an online game, typically a series of powerful bosses that require many players, careful planning and repeated attempts. Raiding guilds built schedules, voice chat and loot rules such as Dragon kill points around it.; Big-group encounters appeared in MUDs and early MMORPGs; EverQuest (1999) and World of Warcraft (2004) made raiding the pinnacle of the endgame.
Railroading: When a Game Master forces the story down a predetermined track regardless of players' choices, like a train that can only go one way. Usually a criticism, it describes blocked exits, invincible villains and plots that happen no matter what the characters do.
Real-time with pause also RTwP: A combat system in which action flows continuously but the player can pause at any moment to issue orders to each party member. It combined the tension of real-time play with the deliberation of turn-based tabletop combat.; Popularized by BioWare's Baldur's Gate (1998) and the Infinity Engine games that followed.
Respawn: The return of a defeated player or monster to the game world after a delay, usually at a set point. Respawning monsters made endless hunting and Grinding possible, and camping respawn points became a notorious online habit.
Retro-clone: A game that uses open game content to restate the rules of an out-of-print edition, usually early D&D, so it can be legally published and played again. Retro-clones such as OSRIC, Labyrinth Lord and Swords & Wizardry powered the Old-School Renaissance (OSR).; The term is usually credited to Goblinoid Games, publisher of Labyrinth Lord (2007); the movement depended on the Open Game License of 2000.
Roguelite also rogue-lite: A game borrowing roguelike elements, such as procedurally generated runs and death that resets progress, while adding permanent upgrades or unlocks that carry between runs, and often real-time action. Darkest Dungeon is a well-known fantasy example.; Emerged in the 2010s as players distinguished such games from traditional roguelikes defined by the 2008 Berlin Interpretation.
Rule zero: The unwritten first rule of many roleplaying games: the Game Master has final say and may change any rule for the good of the game. It underwrites Homebrew and ends many rules arguments.
Rules as written also RAW, RAI, rules as intended: Reading a rule strictly by its text (RAW), as opposed to what its designers meant (RAI, rules as intended). D&D designer Jeremy Crawford has written that ideally the two align, but the words on the page do not always communicate the designers' intent.
Rules lawyer: A player who argues the letter of the rules, often to their own advantage, and treats the rulebook as a legal code. Every table has one; sometimes it is the Game Master.
Safety tools also X-card, Lines and Veils, Session Zero: Techniques that help a group agree on content and stop play when something is unwelcome. Lines rule topics out, veils keep them off-screen, and the X-card lets anyone tap a card to remove content without explanation. Many groups begin with a Session zero to set expectations.; Lines and Veils was named by Emily Care Boss from ideas in Ron Edwards's Sex & Sorcery (2003); the X-card was created by John Stavropoulos in 2013 for convention play.
Sandbox: A game world the player explores freely, choosing goals rather than following a set plot. In tabletop play it describes a campaign where the referee prepares places and factions rather than a storyline; in video games it describes open worlds such as The Elder Scrolls or Minecraft.
Save scumming also savescumming: Reloading a saved game repeatedly to undo bad luck or death, rerolling outcomes until they come up right. The term is especially associated with roguelike players, for whom it defeats the point of Permadeath.
Saving throw also save: A roll made to avoid or reduce a sudden danger such as poison, a dragon's breath, a trap or a spell. The save represents a character's luck, reflexes or willpower rather than an attack, and a success typically negates or halves the effect.; Wargame usage; the term is traced to Donald F. Featherstone's book War Games (1962), and entered roleplaying with Dungeons & Dragons (1974).
Secondary world: An invented world with its own consistent laws, which the reader enters imaginatively and believes in while inside. Tolkien contrasted it with the Primary World of real life and argued that making one well is a genuine art.; Named by J. R. R. Tolkien in his essay On Fairy-Stories, based on a 1939 lecture.
Session zero also session 0: A meeting before a campaign begins in which the group agrees on tone, themes, rules, scheduling and Safety tools, and often creates characters together. It aims to prevent misunderstandings before they reach the table.
Subcreation also sub-creation: Tolkien's term for the human act of making a Secondary world: the author as a sub-creator, working in the image of a greater Creator. It is the theological heart of his defense of fantasy.; J. R. R. Tolkien, On Fairy-Stories (lecture 1939) and the poem Mythopoeia.
THAC0 also To Hit Armor Class 0: The number a character needed to roll on a d20 to hit a target of Armor Class 0; subtract the target's AC to find the roll needed against anything else. It compressed pages of attack tables into one value, but its double negatives became a byword for clunky rules. It was retired when third edition introduced ascending AC in 2000.; Implicit in the combat matrices of AD&D's 1979 Dungeon Masters Guide; it became the core attack rule of AD&D 2nd Edition (1989).
The Chosen One: A protagonist marked by prophecy or bloodline as the only one who can save the world, typically an unassuming youth who discovers a hidden destiny. The trope runs from Arthurian legend through The Belgariad and The Wheel of Time to Harry Potter, and many modern works subvert it.
The Dark Lord: An evil overlord who embodies darkness and seeks domination of the world, usually from a distant fortress. Sauron and Morgoth made the figure a fantasy staple, repeated in countless imitators and games.
The holy trinity also tank / healer / DPS: The three-role party structure of group content: a tank to absorb enemy attention, a healer to keep everyone alive and damage dealers (DPS, damage per second) to kill things. It formalized the fighter-cleric-wizard balance of the tabletop The party for real-time online play.; Commonly traced to EverQuest (1999) and cemented by World of Warcraft (2004).
The magic circle: The boundary that separates a game from ordinary life, inside which special rules and meanings apply. Game scholars debate how porous it is, as when virtual gold sells for real money or a character's grief becomes the player's.; Drawn from Johan Huizinga's Homo Ludens (1938); applied to games by Eric Zimmerman and colleagues and popularized in Katie Salen and Eric Zimmerman's Rules of Play (2003).
The party also adventuring party, fellowship: The group of player characters who adventure together, pooling complementary skills. Its fantasy prototype is the Fellowship of the Ring; its gaming form is the fighter, cleric, wizard and thief of early D&D, carried into computer RPGs and the holy trinity of MMOs.
Theater of the mind: Running scenes, including combat, through description alone, without maps or miniatures, leaving positions and distances to shared imagination. The phrase comes from radio drama.
TPK also total party kill, party wipe: The death of every player character in a single encounter, ending the adventure (and often the campaign). Feared, joked about and occasionally engineered by devious Game Masters, it has an online equivalent in the raid wipe.
Turn-based combat: Combat in which participants act one at a time in a set order, as around a tabletop with Initiative. Standard in early computer RPGs, JRPGs and tactical games, it has enjoyed a revival in games such as Divinity: Original Sin II and Baldur's Gate 3.
Vancian magic also fire-and-forget magic, spell memorization: A magic system in which wizards memorize a limited number of spells each day and forget each one as it is cast. Named after the fantasist Jack Vance, whose Dying Earth magicians could hold only a few formidable spells in mind at once, it defined D&D spellcasting for decades.; Adapted from Jack Vance's The Dying Earth (1950) for Dungeons & Dragons (1974); the name Vancian was applied later by designers and fans.
Wandering monster also random encounter: A creature met by chance rather than placed in a room, determined by rolling on a table at intervals. Wandering monsters make lingering in the dungeon dangerous; their video-game heir is the JRPG random battle.; Wandering monster tables were part of original Dungeons & Dragons (1974).
West Marches: A campaign format with a large, rotating pool of players who schedule their own sessions and head out from a safe town into a dangerous, persistent wilderness. With no set plot, players choose what to explore and share discoveries with one another.; Created by designer Ben Robbins (later the author of Microscope, 2011) and described in his blog posts about the campaign in the late 2000s; its premise has been compared to The Keep on the Borderlands (1979).
Worldbuilding: The craft of inventing an imaginary world's geography, history, cultures, languages and ecology. Tolkien's languages and maps set the modern standard; roleplaying games made worldbuilding a hobby in itself, practiced by every Game Master with a campaign map.

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