What is an illegal serve commonly referred to when executed incorrectly?

In volleyball, the term commonly used to describe an illegal serve is a service error. A service error occurs when the server fails to execute the serve according to the rules, which can include factors such as hitting the net, serving out of bounds, or failing to serve from the correct position. Understanding this terminology is important for players and coaches as it directly impacts the flow of the game and can lead to a point for the opposing team.

While "fault serve" might seem similar, it is a more general term that can encompass a variety of faults that may occur during the serve and other actions within the game. "Missed serve" is not a formal term used in official volleyball terminology to define an illegal serve, and "violation serve" is not recognized as an official term within the context of the rules. Thus, service error accurately captures the specific instance of an illegal serve, making it the correct choice.