noun
: the preliminary stage of alert (as when hostile or unidentified aircraft are nearing a defended area) ; also : the signal for this — compare blue alert , red alert , white alert
noun
: the preliminary stage of alert (as when hostile or unidentified aircraft are nearing a defended area) ; also : the signal for this — compare blue alert , red alert , white alert
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012