Definition: Definitions from the Official Rules of Golf appear
courtesy of the USGA.
Wrong Ball: A "wrong ball" is any ball other than the player's:
• Ball in play,
• Provisional ball, or
• Second ball played under Rule 3-3 or Rule 20-7c in stroke play;
and includes:
• another player’s ball,
• an abandoned ball, and
• the player’s original ball when it is no longer in play.
Note: Ball in play includes a ball substituted for the ball in play whether or not the substitution is permitted.
©USGA, used with permission
