zero hour

noun

Definition of zero hour

1a : 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

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we're at the zero hour, so someone has to make a decision

Recent Examples on the Web

In Act Two, tensions continue to rise and reach their frightful climax at zero hour detonation. — Paul Ross, Popular Mechanics, "I Am Become Opera: An Atomic Show In the Shadow of Los Alamos," 27 July 2018 His business partner Robert Goldfarb then served as the unpaid trustee for a few years, spending zero hours a week on foundation business, according to tax filings. — Andrea Fuller, WSJ, "Private Charitable Foundations Give Lavish Rewards to Insiders," 29 May 2018

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More Definitions for zero hour

zero hour

noun

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