What Greek or IE god or goddess was named "Da"?

Question

This answer claims that the etymology of the name of Greek goddess Demeter is "mother of Da" and the etymology of Poseidon is "husband of Da". Who is Da then?

PS. I seems to be a variant of γῆ?

Answer 1

The form Gdan-Ma (conventionally taken to mean "Earth Mother") is attested in Phrygian, so it's been suggested that Classical Greek Gā/Gē and Mycenaean Da are different ways of simplifying a Pre-Greek (so probably non-Indo-European) name that didn't fit perfectly into Greek phonology.

In other words, according to this theory, "Da" is an alternate name of Gaea, the earth personified.

Answer 2

I think this is a translation issue, but without the original verse it's impossible to verify.

δα– intens. Prefix, = ζα-, as in δάσκιος, δαφοινός.

δάσκιος ον, (< δα, σκιά) thick-shaded, bushy, ὕλη Od. 5.470, B. 10.93, etc. ; ὄρη E. Ba. 218 ; γενειάς A. Pers. 316, S. Tr. 13.

δαφοινός όν (ή, όν Opp. C. 3.440 ; δαφοινή as etym. of δάφνη in Corn. ND 32), epith. of savage animals

in the 2 examples δα is a prefix that elevates the following word to its superlative. So likely in the verse referred to in the other answer it's "Great Mother" (Doric: Δαμάτηρ Dāmā́tēr), not "Mother of da".