M-day

[ em-dey ]

noun

, Military.

1. mobilization day: a day assumed by the Department of Defense as the first day of mobilization, used by the military for planning purposes.

Word History and Origins

Origin of M-day¹

First recorded in 1935–40

Example Sentences

There's ample time for a backlash against the backlash as M-day draws closer and people start feeling millennial peer pressure to make impressive plans.

From Time Magazine Archive

It is difficult to imagine any repetition now of the massive outpourings of M-Day, 1969, or of the angry campus demonstrations of last May, after the invasion of Cambodia.

From Time Magazine Archive

When M-day came to WPB last week, Donald Nelson faced a dilemma of his own making.

From Time Magazine Archive

If the young were the M-day vanguard, many in the ranks wore the housewife's apron and the businessman's necktie, and many who clambered to enlist were political leaders.

From Time Magazine Archive

New York provided an extraordinary juxtaposition of moods as the Mets won the World Series the day after M-day.

From Time Magazine Archive