Glossary

The words players and developers use about how games work, from the feel of a jump to the code that keeps online matches in sync. Each entry explains the term, gives the earliest documented use we could find, and links to games, genres and engines. For the longer story behind two of them, read why PC games stutter.

Movement and feel

• Animation cancelling: Stopping a character’s action partway through its animation to start a different one.
• Bunny hopping: Bunny hopping chains jumps together while strafing and turning, so the player builds speed beyond the game’s intended maximum.
• Coyote time: A short grace period, typically a few frames, in which a jump still works after the character has run off a ledge.
• Frame data: The set of numbers that describe each move in a fighting game, counted in frames: startup before the move can hit, active frames when it can hit, and recovery before the character can act again.
• Game feel (juice): The tactile sense of controlling a game: how a jump or a hit responds and lands.
• Hitbox and hurtbox: The invisible area of an attack that can deal damage; a hurtbox is the area of a character that can take it.
• Hitstop: A brief pause, a few frames long, when an attack connects.
• I-frames (invincibility frames): Frames during which a character cannot take damage, because the game ignores the character’s hurtbox.
• Input buffering: Input buffering stores a command entered while the character cannot act yet, such as during another move, and carries it out at the first frame it becomes possible.
• Rocket jumping: Firing an explosive, usually a rocket, at your feet or a nearby surface so the blast launches you higher or farther than a normal jump.
• Screen shake: A short, quickly fading jolt of the camera when something hits, lands or explodes.
• Strafe jumping: Strafe jumping raises movement speed in Quake-engine games: the player jumps repeatedly while holding a strafe key and turning the view.

Online play

• Delay-based netcode: Delay-based netcode holds back each player’s own inputs until the other player’s inputs arrive, so both machines run the same frames together.
• Hitscan: A hitscan weapon hits whatever lies along its line of fire at the instant you shoot; there is no projectile with travel time.
• Lag compensation: Lag compensation lets the server judge a shot by what the shooter saw.
• Matchmaking (MMR/Elo): How an online game puts players together in a match.
• Netcode: The umbrella word for how an online game keeps players in sync: the network architecture, which machine has authority, and the techniques that hide latency, such as lag compensation and rollback.
• Rollback netcode: Rollback netcode runs your inputs immediately, predicts the remote player’s inputs, and when a prediction turns out wrong, rewinds and replays the frames with the real input.
• Rubber-banding (network): A visible effect of network latency: a moving player or object jumps from one place to another, or snaps back to an earlier position.
• Spawn killing: Killing other players at their spawn point, often right after they come back into the game.
• Tick rate: A tick is one update of a game’s simulation, and the tick rate is how many ticks the server runs per second, measured in hertz.
• TTK (time to kill): How long it takes to kill an opponent with a given weapon, from the first shot that lands to the kill.

AI and difficulty

• Aggro: The hostile attention of enemies: a monster with aggro on you attacks you.
• Dynamic difficulty adjustment: Dynamic difficulty adjustment changes a game’s parameters, scenarios and enemy behaviour while you play, based on how well you are doing.
• Kiting: Getting an enemy to chase you, like a kite on a string, while you stay out of its reach and hit it from range.
• Level scaling: Level scaling adjusts the strength of enemies, or of the player, as the player levels up, so that fights stay about as challenging as before.
• Permadeath: Death is final: a character who dies cannot be used again, and in many games the run or save file ends with it, so you start again from the beginning rather than reloading.
• Rubber-band AI: Rubber-band AI keeps a race close by bending the rules: computer opponents speed up when they fall behind and slow down when they lead, as if tied to the player by a rubber band.

Progression and economy

• Battle pass: A reward track that runs for a season.
• Gacha: A game mechanic named after gashapon, the Japanese capsule toy machines.
• Grinding: Repeating a task, such as defeating the same enemies, to collect experience, currency or items before you can progress.
• Live service game: Sold or run as an ongoing service rather than a finished product: the publisher keeps adding content in seasons and updates and earns continuing revenue from it, much like software as a service.
• Loot box: A virtual container that gives a random selection of items from a pool weighted by rarity.
• Meta-progression: Progress that survives the end of a run or session: currency, unlocks or upgrades that carry over while the rest of the game resets.
• Nerf and buff: A change, usually in a patch, that weakens an item, ability, tactic or character; a buff makes one stronger.
• New Game Plus: A mode, usually unlocked by finishing a game, that starts the story again while letting you keep some or all of your items, levels or equipment from the first playthrough.
• Pity timer: A safety net in gacha games and card packs: the game counts how many pulls pass without a top-rarity result and guarantees one after a set number.
• Power creep: The gradual unbalancing of a game as new content keeps arriving a little stronger than what came before, until older options are no longer worth using.
• The meta: The meta, short for metagame, is the set of strategies, characters or builds that players currently consider strongest.

Design and world

• Easter egg: A message, image or feature hidden in a game by its makers.
• Emergent gameplay: What happens when relatively simple game systems interact and produce complex situations the designers did not script, or when players find uses for the systems that the designers never planned.
• Fast travel: Fast travel lets you jump straight to a place you have already discovered instead of crossing the distance in real time.
• Fog of war: Fog of war hides enemy units, and often the terrain, until your own units see them.
• Ludonarrative dissonance: A conflict between the story a game tells in its cutscenes and dialogue and the story its gameplay tells through what it asks and rewards.
• Procedural generation: Procedural generation creates game content with algorithms rather than by hand: levels, dungeons, planets, item stats.
• Quick time event (QTE): A moment where the game shows a button prompt and gives you a short window to press it.
• Save scumming: Reloading a saved game, or copying save files, to undo a bad outcome or reroll a random one until it goes your way.
• Sequence breaking: Getting items or reaching areas out of the order the designers intended, or skipping required steps.
• Softlock: A state where progress has become impossible even though the game still runs and responds.
• Tech tree: A tech tree lays out the upgrades a player can unlock and the order they must come in: each technology needs one or more earlier ones.

Rendering and performance

• Frame generation: Frame generation creates extra frames between the ones the game actually renders, by interpolating between two of them.
• Frame pacing: The evenness of the gaps between frames shown on screen.
• Level of detail (LOD): Drawing distant objects with simpler models than near ones.
• Pop-in: The sudden appearance of objects or terrain as the camera gets closer, or a visible jump in an object’s detail.
• Ray tracing: Ray tracing renders light by following the paths of rays through a scene, which gives accurate reflections, shadows and indirect lighting.
• Shader compilation stutter: A hitch that happens when a game compiles a shader, a small graphics program, at the moment it first needs it.
• Upscaling (DLSS/FSR): Upscaling renders most of each frame at a lower resolution and then reconstructs a higher-resolution image from it, which raises performance.