Cutscene
The moment the game takes the controller away to tell you something — either as pre-rendered video or played out in the engine itself.
The word is usually credited to Ron Gilbert, who used it for the short scenes in Maniac Mansion (1987) where the game cuts away to something happening elsewhere in the house. Technically there are two schools. Pre-rendered sequences are video, often Bink, and can look as lavish as the budget allows but never sharper than the resolution they were encoded at. In-engine sequences are driven by a timeline script, as in Cinemachine, and show the player's actual gear and world.
Half-Life (1998) became famous for almost doing without: the story happens around the player, who never loses control. That remains the expensive option, because every scene then has to survive someone bunny-hopping in the corner.