A serve that strikes the net before falling into the receiver's court; the ball must be served again; SYN. net ball.

ETYM Old Eng. letten, as. lettan to delay, to hinder, from laet slow; akin to Dutch letten to hinder, German verletzen to hurt, Icel. letja to hold back, Goth. latjan. Related to Late.
(Irregular preterit, past participle: let).
1. To actively cause something to happen.
2. To make it possible through lack of action for something to happen; SYN. allow, permit.