Bulla (Latin) means bubble, bauble, trifle, vanity, inflated, expanding quickly and quickly passing; whence comes the Papal Bull or edict named for the hot bubb
Hillman derives the psychological resonance of 'bubble' from its Latin root bulla, establishing inflation, vanity, and transience as the term's archetypal semantic core within his mythopoetic lexicon.
, Animal Presences, 2008thesis