Dictionary.com

zero hour

Save This Word!

noun
the time set for the beginning of a military attack or operation.
the time set for the beginning of any event or action.
a decisive or critical time.
QUIZ
QUIZ YOURSELF ON AFFECT VS. EFFECT!
In effect, this quiz will prove whether or not you have the skills to know the difference between “affect” and “effect.”
Question 1 of 7
The rainy weather could not ________ my elated spirits on my graduation day.
Meet Grammar CoachWrite or paste your essay, email, or story into Grammar Coach and get grammar helpImprove Your Writing
Meet Grammar CoachImprove Your Writing
Write or paste your essay, email, or story into Grammar Coach and get grammar help

Origin of zero hour

First recorded in 1915–20
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022

How to use zero hour in a sentence

British Dictionary definitions for zero hour

zero hour

noun
military the time set for the start of an attack or the initial stage of an operation
informal a critical time, esp at the commencement of an action
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
FEEDBACK