Hypothetically related to Proto-Altaic *ĕ́t`è (“elder relative”), Proto-Dravidian *átai (“female relative (father's sister; grandmother)”) and Proto-Eskimo *ata-ata, *ata (“father”), Sumerian 𒀜𒁕 (AD.DA). The meaning "father" (somewhat expectable from a root like ata-) is actually present in Tamil and Malayalam, but nowhere else in Dravidian. The archaicness of this meaning in Tamil cannot be excluded; more probable, however, is the idea that in Tamil the word has developed a parallel masculine stem by analogy with Proto-Dravidian *ápa (“father (honorary)”). The latter does have 'masculine' meanings outside of Tamil.
- Albanian: atë (attest. 1462, Skanderbeg's counselor)
- Celtic: *attyos
- Germanic: *attô
- Ancient Greek: ἄττα (átta)
- Ossetic: ӕда (æda, “grandfather”)
- Latin: atta
- Slavic: *otьcь (< *otъ + *-ьcь) (see there for further descendants)