Let Serve
A serve that clips the top of the net but still crosses over to the opponent's side. Under FIVB, NCAA, and most other rule sets, the ball is live and play continues. The net contact can change the ball's trajectory unpredictably, making it harder to pass.
Example
A net cord pulls the float down in front of a seam that thought it had depth. The ball bounces in before anyone moves.
Frequently Asked Questions
Is a let serve legal in volleyball?
Yes. FIVB brought that rule years ago, NCAA followed, and high school in the U.S. is on the same page. If it clears and lands in, play on; if it dies in the net, it is a service error.