isthmus (n.)youdaoicibaDictYouDict[isthmus 词源字典]
1550s, from Latin isthmus, from Greek isthmos "narrow passage, narrow neck of land," especially that of Corinth, of unknown origin, perhaps from eimi "to go" + suffix -thmo (compare ithma "a step, movement").[isthmus etymology, isthmus origin, 英语词源]