What is meant by "line violation" during service?

The term "line violation" during service specifically refers to the act of stepping on or over the boundary line while executing a serve. In volleyball, the server must remain behind the service line until they make contact with the ball. If the server's foot touches or crosses this line before the serve, it constitutes a line violation, resulting in a point for the opposing team. This rule is in place to ensure fairness and maintain proper serving protocols.

The other options describe different infractions related to serving but do not accurately represent what a line violation is. Failing to serve from behind the service line indicates a broader issue of positioning, serving before the whistle pertains to timing, and using improper techniques focuses on the execution of the serve rather than the act of crossing the line itself.