in antiquity, a measure used by the ancients, equal to one-eighth of our pint. It seems to have acquired its name from a vessel in which acetum or vinegar was brought to their tables, and which probably contained about this quantity.

in Anatomy, a cavity in any bone for receiving the protuberant head of another, and thereby forming that species of articulation called Exarthrosis.

in Botany, the trivial name of a species of the peziza, or cup peziza, a genus belonging to the cryptogama fungi of Linnæus. It has got the name of acetabulum from the resemblance its leaves bear to a cup.