4s COMPLETION OF A FRAME OR GAME.
A frame is over when the black is potted on a legal shot (rule 5d) and all balls come to rest OR in a loss of frame situation (rule 7).
The referee waits for the balls to stop moving and announces frame, game or match awarded to a player or team.
If the referee has not made this announcement and the balls are still moving, then a player will be penalized by loss of frame if a further shot is played OR the player interferes with the remaining balls.