taryoudaoicibaDictYouDict[tar 词源字典]
tar: [OE] Tar is etymologically a substance produced from ‘trees’. The word goes back via a prehistoric Germanic *terw- (source also of German and Dutch teer, Swedish tjära, and Danish tjære) to Indo-European *drew- ‘tree’ (source of English tree) – the original application of the word evidently having been to the tarry resins produced by conifers. (The tar [17] of Jack tar ‘sailor’ is short for tarpaulin [17], a compound noun probably formed from tar and pall ‘covering’.)
=> tree, trough[tar etymology, tar origin, 英语词源]
tar (n.2)youdaoicibaDictYouDict
also Jack Tar, "sailor," 1670s, probably a special use of tar (n.1), which stuff was a staple for waterproofing aboard old ships (sailors also being jocularly called knights of the tarbrush); or possibly a shortened form of tarpaulin, which was recorded as a nickname for a sailor in 1640s, from the tarpaulin garments they wore.