zero hour

zero hour

noun

: the time at which an event (such as a military attack) is scheduled to begin

Full Definition of ZERO HOUR

1

a :  the hour at which a planned military operation is scheduled to start

b :  the time at which a usually significant or notable event is scheduled to take place

2

:  a time when a vital decision or decisive change must be made

Examples of ZERO HOUR

1. <we're at the zero hour, so someone has to make a decision>

Origin of ZERO HOUR

from its being marked by the count of zero in a countdown

First Known Use: 1917

Related to ZERO HOUR

Synonyms

boiling point, breaking point, clutch, conjuncture, crisis, crossroad(s), crunch, crunch time, Dunkirk, exigency, extremity, flash point, head, juncture, tinderbox, emergency

Related Words

contingency, possibility; climax, turning point; happening, landmark, milestone; condition, pass, situation, strait; deadlock, impasse, stalemate; corner, fix, hole, hot water, jam, last ditch, pinch, predicament, scrape, spot; eleventh hour, last minute

Rhymes with ZERO HOUR

coffee hour, cooling tower, credit hour, flower power, golden shower, happy hour, ivory tower, motive power, police power, quarter hour, staying power, trumpet flower, virgin's bower, water tower