Defense alert
A defense alert was a type of generalized alert used by Starfleet in the 23rd century to indicate danger from a possible imminent threat.

In 2268, when the  was summoned to Deep Space Station K-7 on a priority 1 distress call, Captain James T. Kirk was aghast that Undersecretary in Charge of Agricultural Affairs Nilz Baris would place an entire quadrant on defense alert when there was no apparent emergency. ()
Alerts