dubyoudaoicibaDictYouDict[dub 词源字典]
dub: English has two words dub. By far the older, ‘create a knight, name’ [11], was one of the first linguistic fruits of the Norman conquest, which was during the Middle English period to contribute such a vast number of French words to the English language. It came from Anglo- Norman duber, which was a reduced form of aduber, the Anglo-Norman version of Old French adober.

This meant ‘equip, repair, arrange’, but also specifically ‘equip with armour’, which led metaphorically to ‘confer the rank of knighthood on’. The sense ‘arrange’ has remained in use in various technical areas up to the present time, and its application to the dressing of leather with grease formed the basis of the noun dubbin ‘mixture of oil and tallow for softening and waterproofing leather’ [18]. Dub ‘insert soundtrack’ [20] is a shortened version of double.
=> dubbin; double[dub etymology, dub origin, 英语词源]
dub (v.1)youdaoicibaDictYouDict
"give a name to," originally "make a knight," from late Old English dubbian "knight by striking with a sword" (11c.), a late word, perhaps borrowed from Old French aduber "equip with arms, adorn" (11c.) which is of uncertain origin, but there are phonetic difficulties. Meaning "provided with a name" is from 1590s. Related: Dubbed; dubbing.
dub (v.2)youdaoicibaDictYouDict
"add or alter sound on film," 1929, shortening of double; so called because it involves re-recording voices onto a soundtrack. The type of re-mixed reggae music was so called from 1974, probably for the same reason. Related: Dubbed; dubbing.