onyoudaoicibaDictYouDict[on 词源字典]
on: [OE] On is an ancient Germanic preposition, with relatives in German (an), Dutch (aan), and Swedish (å), and also connections outside Germanic (such as Greek aná ‘on’ and Russian na ‘on’)
[on etymology, on origin, 英语词源]
on (prep.)youdaoicibaDictYouDict
Old English on, unstressed variant of an "in, on, into," from Proto-Germanic *ana "on" (cognates: Dutch aan, German an, Gothic ana "on, upon"), from PIE root *an- "on" (cognates: Avestan ana "on," Greek ana "on, upon," Latin an-, Old Church Slavonic na, Lithuanian nuo "down from"). Also used in Old English in many places where we would now use in. From 16c.-18c. (and still in northern England dialect) often reduced to o'. Phrase on to "aware" is from 1877. On time is from 1890.