A point in the game when the referee or a linesman is about to blow the whistle or must wait to blow the whistle, most likely due to a delayed penalty or offside.
Referees must wait to blow a whistle when a team that has committed an infraction does not have possession or control of the puck. This is known as a delayed penalty.
Linesmen also may have a delayed whistle when teams are in an offside situation. If the team then touches the puck or contacts the opposing team, the linesman will blow play dead.
One of the more confusing rules of a "delayed whistle" situation is when a referee has lost sight of the puck and in the time it takes to get his whistle to his mouth, a team scores a goal. Even though the goal is scored before the whistle went, the goal is not allowed since in the referee's mind the play had been stopped because he lost sight of the puck.