tarn (n.)youdaoicibaDictYouDict[tarn 词源字典]
late 14c., mid-13c. in Anglo-Latin, from Old Norse tjörn "small mountain lake without visible tributaries," from Proto-Germanic *terno, perhaps originally "water hole" [Barnhart]. A dialectal word popularized by the Lake poets.[tarn etymology, tarn origin, 英语词源]