Sprint is the core delivery unit in Scrum: a fixed-length time box (typically 2–4 weeks in game development) during which the team selects backlog items, builds them to the Definition of Done, and produces a playable increment. Every sprint begins with planning and ends with a review (playtesting / demonstration) and a retrospective. The Sprint Goal gives the sprint a single coherent objective that the team commits to (Keith 2021, see source-agile-game-development).
Sprints enforce the inspect-and-adapt cycle: each sprint end is an opportunity to re-prioritise based on what was learned by playing the game.
Related: sprints, scrum-in-game-development, product-backlog, velocity, definition-of-done