Meaning of ALERT in English

ALERT

n.

Function: noun

Date: 1803

1 : a state of careful watching and readiness especially for danger or opportunity <on 24-hour alert >

2 a : an alarm or other signal of danger b : an urgent notice <an alert to parents ⋯ about new immunization requirements ― Ann Schrader>

3 : the period during which an alert is in effect

Merriam Webster Collegiate English Dictionary.      Merriam Webster - Энциклопедический словарь английского языка.