ETYM Prob. of Celtic origin; cf. Irish daid, Gael. daidein, W. tad, OL. tata, Greek tata, tetta, Skr. tâta.
An informal term for a father; probably derived from baby talk; SYN. dada, daddy, old man, pa, papa, pappa, pater, pop.

Diminutive of Dad.

ETYM French papa, Latin papa; cf. Greek pater, a child's word meaning father. Related to Pope.
A child's word for father.