thine (pron.)youdaoicibaDictYouDict[thine 词源字典]
Old English þin, possessive pronoun (originally genitive of þu "thou"), from Proto-Germanic *thinaz (cognates: Old Frisian, Old Saxon thin, Middle Dutch dijn, Old High German din, German dein, Old Norse þin), from PIE *t(w)eino-, suffixed form of second person singular pronominal base *tu-. A brief history of the second person pronoun in English can be found here; see also thou.[thine etymology, thine origin, 英语词源]