Countdown
来自Big Physics
Safin（讨论 | 贡献）2022年4月28日 (四) 02:39的版本 （建立内容为“Category:etymology == wiktionary == [https://en.wiktionary.org/wiki/countdown ref] From count + down. == etymonline == [https://www.etymonline.com/wo…”的新页面）
wiktionary
From count + down.
etymonline
countdown (n.)
also count-down, "the counting down of numerals in reverse order to zero before a significant event," also the preparations made during this time, 1953, American English, in early use especially of launches of rockets or missiles, from the verbal phrase (attested by 1954); see count (v.) + down (adv.).
