ridgeyoudaoicibaDictYouDict[ridge 词源字典]
ridge: [OE] Old English hrycg denoted ‘the back’, as its modern Germanic relatives – German rücken, Dutch rug, Swedish rygg, and Danish ryg – still do. But a gradual semantic focussing on the ‘backbone’ led by the 14th century to the emergence of ‘long narrow raised area’, today’s main meaning. It goes back to a prehistoric Germanic *khrugjaz, which may have been related to Sanskrit krunc- ‘be crooked’ – in which case the notion underlying the word would be of a ‘bent back’.
[ridge etymology, ridge origin, 英语词源]
focus (v.)youdaoicibaDictYouDict
1775 in optics, "bring into focus" (transitive); 1807 in the figurative sense, from focus (n.). Intransitive use by 1864, originally in photography. Related: Focused; focusing; less commonly focussed; focussing.