Clearance
来自Big Physics
Safin（讨论 | 贡献）2022年4月27日 (三) 13:15的版本 （建立内容为“Category:etymology == wiktionary == [https://en.wiktionary.org/wiki/clearance ref] clear + -ance == etymonline == [https://www.etymonline.com/word/cle…”的新页面）
wiktionary
clear + -ance
etymonline
clearance (n.)
1560s, "action of making clear," from clear (v.) + -ance. Meaning "a clear space" is from 1788. Meaning "approval, permission" (especially to land or take off an aircraft) is from 1944, American English; national security sense recorded from 1948. Clearance sale attested by 1843.
