When you list a sequence of numbers in reverse order, ending in zero, that's a countdown. When you're preparing to launch your model rocket, you can make it more exciting with a countdown!

"Five, four, three, two, one, blast off!" is a countdown that may sound familiar if you've ever watched footage of a NASA space shuttle launch. You might also hear a countdown on New Year's Eve, as revelers count down the seconds until midnight and the beginning of a new year. This word comes from American English, first appearing in the 1950s in the context of rocket launches.

Definitions of countdown
  1. noun
    counting backward from an arbitrary number to indicate the time remaining before some event (such as launching a space vehicle)
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    type of:
    count, counting, enumeration, numeration, reckoning, tally
    the act of counting; reciting numbers in ascending order
Word Family

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