zero hour

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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Examples of zero hour in a Sentence

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

Recent Examples on the Web Major milestones in the emergency plan are performed according to a predetermined schedule in the hours and days leading up to the zero hour. — Daniel B. Hess, CNN, "How do hospitals prepare for hurricanes?," 2 Sep. 2019 Major milestones in the emergency plan are performed according to a predetermined schedule in the hours and days leading up to the zero hour. — Daniel B. Hess, CNN, "How do hospitals prepare for hurricanes?," 2 Sep. 2019 Major milestones in the emergency plan are performed according to a predetermined schedule in the hours and days leading up to the zero hour. — Daniel B. Hess, CNN, "How do hospitals prepare for hurricanes?," 2 Sep. 2019 Major milestones in the emergency plan are performed according to a predetermined schedule in the hours and days leading up to the zero hour. — Daniel B. Hess, CNN, "How do hospitals prepare for hurricanes?," 2 Sep. 2019 Major milestones in the emergency plan are performed according to a predetermined schedule in the hours and days leading up to the zero hour. — Daniel B. Hess, CNN, "How do hospitals prepare for hurricanes?," 2 Sep. 2019 Major milestones in the emergency plan are performed according to a predetermined schedule in the hours and days leading up to the zero hour. — Daniel B. Hess, CNN, "How do hospitals prepare for hurricanes?," 2 Sep. 2019 Major milestones in the emergency plan are performed according to a predetermined schedule in the hours and days leading up to the zero hour. — Daniel B. Hess, CNN, "How do hospitals prepare for hurricanes?," 2 Sep. 2019 Major milestones in the emergency plan are performed according to a predetermined schedule in the hours and days leading up to the zero hour. — Daniel B. Hess, CNN, "How do hospitals prepare for hurricanes?," 2 Sep. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'zero hour.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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Learn More about zero hour

Dictionary Entries near zero hour

zero-lift angle

Statistics for zero hour

Last Updated

9 Jan 2020

Cite this Entry

“Zero hour.” The Merriam-Webster.com Dictionary, Merriam-Webster Inc., https://www.merriam-webster.com/dictionary/zero%20hour. Accessed 18 January 2020.

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