surname, from 13c. Scottish Dofnald, Dufenald, probably from Gaelic Domhnall, Old Irish Domnall (pronounced "Dovnall"), from Proto-Celtic *Dubno-valos "world-mighty, ruler of the world," from *walos "ruler" + PIE *dheub- (see deep (adj.)).[Donald etymology, Donald origin, 英语词源]