爸爸,爹爹
Dad \Dad\, n. [Prob. of Celtic origin; cf. Ir. daid, Gael. daidein, W. tad, OL. ?, ?, Skr. t[=a]ta.] Father; -- a word sometimes used by children. I was never so bethumped withwords, Since I first called my brother's father dad. --Shak.
dad n : an informal term for a father; probably derived from baby talk [syn: {dada}, {daddy}, {pa}, {papa}, {pappa}, {pater}, {pop}]