Standby

Also called: Warning (US)

The stage manager's heads-up that a cue is coming soon. Operators answer "standing by" and keep their finger ready.

US practice adds an earlier "warning" about a page ahead, then "standby" just before the GO. Usage differs: some UK guides treat warn as simply the American word for standby, while US handbooks treat them as two steps, a warning about a minute out and a standby just before the go.