Proto-IE: *bōul-
Meaning: round obj., bubble
Old Greek: *bülló-: büllá = bebusména Hsch.; bō̂lo-s f. (/m.) `(Erdk)loss, Erdscholle'
Latin: bulla f. `(Wasser)blase, Buckel, Knospe, Knopf, Golldkaspel mit Amulett'
Russ. meaning: круглый предмет, пузырь
References: WP II 111 f