Acetabulum (Greek: ὀξίς, ὀξύβαφον, ὀξυβάφιον) was a Roman vinegar-cup, which was presumably placed on the table at meals, so the eating could dip their food in it before eating it. The vessel was wide and open above, and the name was also used for all cups resembling it in size and form. Acetabulae were commonly made of clay, but at times also from silver, bronze or gold. The cups used by jugglers in their performances were also called acetabulum (Seneca, epistulae morales ad lucilium, 45).
- Smith, W. (1878). A dictionary of Greek and Roman antiquities. London: J. Murray, a work that is now in the public domain.