countdown

• count down
• count-down

From count +‎ down.

• (noun) IPA^(key): /ˈkaʊntˌdaʊn/

countdown (plural countdowns)

1. A count backward in fixed units to the time of some event, especially the launch of a space vehicle.
2. The acts of preparation carried out during this period.
3. A radio or television program counting down the top songs of a given week, usually in reverse order ending with the No. 1.

countdown (third-person singular simple present countdowns, present participle countdowning, simple past and past participle countdowned)

1. (nonstandard) To count down.
   • 1994, Yifeng Yuan, Polarized fluorescence photobleaching for measuring fast rotational motion of cell surface receptors:

     This was accomplished in the old system by polling a software variable representing the number of prebleach bin and issuing a software command to trigger the AOM once the variable has countdowned to zero.

   • 2000, Stephen Mark Cox, Cluck:

     Time measures itself out in a series of diminishing peristaltic ticks, countdowning slowly towards the miracle of Ignition.

   • 2003, Edward Stone Cohen, Firewater, →ISBN, page 129:

     Whole families stood gawking at the massive statue, countdowning the five remaining minutes to the big one.