Proto-IE: *pun-
Meaning: hollow (in the egg), anus
Old Greek: pǘnnos = ho prōktós Hsch. (LS Suppl.267); {pünniáinein = peraínein, hōs arrénōn - not found!}; pouniázdein = paidikoîs khrē̂isthai, poúnion gàr ho daktǘlios Hsch., pünniázdō id. Hsch.
Russ. meaning: полость (в яйце), anus
References: Fraenkel 666