détenteyoudaoicibaDictYouDict[détente 词源字典]
détente: [20] English originally acquired this word from French in the 17th century as detent, which denotes a catch that regulates the movement of a clock. French détente, which originally signified a device for releasing a crossbow string, came from the past participle of Old French destendre ‘release’, a compound verb formed from the prefix des- ‘apart’ and tendre ‘stretch’ (related to English tension).

But English-speakers, mistakenly associating it with detain [15] (a verb of completely different origin, via Old French detenir from Latin dētinēre ‘keep back’) completely reversed its meaning, applying to a restraining catch rather than a releasing one. French, the language of diplomacy, re-lent détente to English in the first decade of the 20th century in the sense ‘relaxation of international tension’.
=> tension[détente etymology, détente origin, 英语词源]
detente (n.)youdaoicibaDictYouDict
1908 as a political term, a borrowing of French détente "loosening, slackening" (used in the Middle Ages for the catch of a crossbow), from Vulgar Latin detendita, fem. past participle of Latin detendere "loosen, release," from de- "from, away" (see de-) + tendere "stretch" (see tenet). The reference is to a "relaxing" in a political situation. The French word was earlier borrowed as detent (1680s) "catch which regulates the strike in a clock."