countdown

[ kount-doun ]
/ ˈkaʊntˌdaʊn /

noun

the backward counting in fixed time units from the initiation of a project, as a rocket launching, with the moment of firing designated as zero.
the final preparations made during this period.
a period of increasing activity, tension, or anxiety, as before a deadline.

Origin of countdown

1950–55, Americanism; noun use of verb phrase count down
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for countdown

British Dictionary definitions for countdown

countdown

/ (ˈkaʊntˌdaʊn) /

noun

the act of counting backwards to time a critical operation exactly, such as the launching of a rocket or the detonation of explosives

verb count down (intr, adverb)

to count numbers backwards towards zero, esp in timing such a critical operation
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012