Definitions for "Zero Hour"
"Zero Hour" is the title of an episode of Star Trek: Enterprise; it was the season finale for season three. The episode was the end of a season-long story arc in which the crew of the Enterprise try to stop the Xindi-reptilians from destroying Earth.
Zero Hour is a Canadian-made, British produced, documentary-style television program, which airs on The History Channel in the United States, Canada, and the BBC in the United Kingdom. Zero Hour has been shown on Channel Seven in Australia and on Discovery Channel in Asia and New Zealand. The program focuses on retelling the details of tragic man-made disasters that unfolded in less than an hour.
Zero Hour: Crisis in Time was a 1994 comic book miniseries and crossover storyline that ran in DC Comics. In it, the one-time hero Hal Jordan, who had until then been a member of the intergalactic police force known as the Green Lantern Corps, mad with grief after the destruction of his home town of Coast City, and having obtained immense power as Parallax, attempted to destroy, and then remake, the DC Universe. The crossover involved almost every DC Universe monthly series published at the time.
Keywords:  start, action, operation, set, time
the time set for the start of an action or operation