Countdown

A countdown is a series of numbers getting lower in value towards zero. Usually something will happen when the counter finishes.

Countdown Media

2015 FIFA Women's World Cup countdown at Champlain Place, Dieppe, New Brunswick
Countdown clock at NASA's Kennedy Space Center at L-11 hours (28 April 2011) of STS-134, Space Shuttle Endeavour.
Seven seconds after launch of STS-121, the countdown clock at LC-39 at the Kennedy Space Center seen counting up, rather than down.
Newer (1959) SMPTE countdown on the head leader of a film reel

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