Recently possible PIE *h2o:ujom 'egg' < (some adjectival vrddhi)
*h2awi-/*h2w(e)i- was discussed. Two more moments.
1. Curiously enough, Burrow in The Sanskrit Language gives a nearly
exactly inverse explanation: he postulates PIE i-stem neutral *o:'wi
(he says root vrddhi is 'often' with i- and u-stems) 'egg' and then
explains Greek <o:I~on> 'egg' < *o:'wjom as a mere o-extension of
*o:'wi; Sanskrit <vi'-> is explained as an adjectival derivation from
*o:'wi, elision of *o: being the result of the retraction of stress
from the root to the suffix; he writes that gun.a in Vedic <ve's> is
unusual for such derivatives (like <dyau's> 'sky(-god)' and <gau's>
'cow', so he seemes to expect **vai's here).
2. It's often stated that Lithuanian <vis^ta`> and Lettish <vista>
'hen' are cognates of Old Indic <vi'->/<ve'-> and Avestan vi:s^
'bird', Latin <avis> etc. But where does that Baltic *-s't-a: < *-st-
ah2 / -k^t-ah2 come from? The suffix looks rather unusually.
Sergei