Final answer:
An umpire calls 'out of court' when the ball goes outside the boundaries of the playing area in sports like volleyball or basketball. They do not need to blow their whistle for this call.
Step-by-step explanation:
An umpire calls 'out of court' in sports like volleyball or basketball when the ball goes outside the boundaries of the playing area. They do not need to blow their whistle for this call. The decision is usually made based on the position of the ball and the player's body parts in relation to the lines that mark the court boundaries.