from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun The scheduled time for the start of an operation or action, especially a combat operation of great size.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun The scheduled time for the start of some event, especially a military operation; H-hour

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • noun the time set for the start of an action or operation


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