countdown

Etymology

From count + down.

noun

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.

verb

1. (nonstandard) To count down.
   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. 1994, Yifeng Yuan, Polarized fluorescence photobleaching for measuring fast rotational motion of cell surface receptors
   Time measures itself out in a series of diminishing peristaltic ticks, countdowning slowly towards the miracle of Ignition. 2000, Stephen Mark Cox, Cluck
   Whole families stood gawking at the massive statue, countdowning the five remaining minutes to the big one. 2003, Edward Stone Cohen, Firewater, page 129