bulla

1. A blister, vesicle, or other thin-walled cavity or lesion, as
2. A blister, vesicle, or other thin-walled cavity or lesion, as:
3. A clay envelope or hollow ball, typically with seal impressions or writing on its outside indicating its contents.
4. (historical) In ancient Rome, a kind of amulet or boss.
5. Later, a handwritten document from the papal chancellery.
6. Any of several hollow structures as features of bones.
7. Any of several hollow structures as features of bones.

Etymology

Borrowed from Latin bulla (“bubble”). Doublet of bill and bull (“papal bull; bubble”).

Synonyms

blister

vesicle

bleb

gallbladder

vesica

water blister

artillery gun

water clock

bull

clepsydra