is it 'in a belly' (singular) or 'ewe's mil' as some might say, or what?

From Wikipedia, http://en.wikipedia.org/wiki/Imbolc I found this definition.

In Irish, Imbolc means "in the belly" (i mbolg), referring to the pregnancy of ewes, and is also a Celtic term for spring. Another name is Oimelc, meaning "ewe's milk".

I don't know if the above is correct, but I thought I would mention it.

Etymology

From Old-Irish-L, July 1999:

Jim Rader:

The two forms and are discussed in detail--maybe a lot more detail than some would wish--by Eric Hamp in _Studia Celtica_, v. 14/15 (1979/80), p. 106-113. Hamp's conclusion, the intricate justification of which I can't attempt to summarize, is that both and are folk-etymological reshapings of an unattested <*ommolg>.

Me:

Fergus Kelly has edited an OI legal text on distraint of livestock in _Early Irish Farming_ which includes the expression "bai occ omulc", which he translates "cows being milked", with "omulc" treated as the dative singular of the unattested verbal noun *omalc, from *uss-mlig-. That certainly fits Hamp's *ommolg.

Jim:

If one form is older than the other, perhaps it is , which preserves the original vocalism of the first syllable (though Hamp doesn't actually say this).

Me:

It's worth noting in passing that "oímelc" is a word (not unlike the famous "[C]ernunnos"), that has come down to us in just one single attestation, in this case as an entry in Cormac's Glossary (where the initial "o" or "i" is marked long - scribes were notoriously indifferent as to which vowel in the "oi" pair actually carried the accent mark). Kelly refers to Hamp, but speculates that "Oímelc here seems to be a glossator's deformation of the word 'Imbolc' to provide an explanatory etymology. [oi-melg = sheep's milk]".