Etymology: Probably < the (reduplicated) syllable /da/ which is characteristic of early infantile vocalization, with loss of the final vowel. Slightly earlier currency is probably implied by daddy n. Compare also later dada n.¹It has been suggested that the word was borrowed from Welsh tad , also inflected (with soft mutation, e.g. in the vocative) dad father (12th century; not restricted to informal use); compare Old Cornish tat (Middle Cornish tas , Cornish taz ), Middle Breton tat (Breton tad ); however, this is more likely to reflect a parallel formation, which superseded the Celtic cognate of father n. in these languages. Superficially similar words for ‘father’ also occur in other languages around the world; these are parallel formations and not etymologically related. Compare e.g. Sanskrit tata , tāta , ancient Greek τέττα , Hellenistic Greek τατᾶ , classical Latin tata , Polish tata , and also (without initial consonant) e.g. ancient Greek ἄττα , classical Latin atta (attested in an 8th-century epitome of a 2nd-century grammarian), Gothic atta , Turkish ata . With quot. 1533 at sense 1a compare Abba, father at Abba n.¹ 1.

Etymology: Euphemistic alteration of Gad n.² or its etymon god n., probably after dad n.¹ (compare father n. 2). Compare adad int. and also dod n.¹ and int.