Patera

·noun A circular ornament, resembling a dish, often worked in relief on friezes, and the like.

II. Patera ·noun A saucerlike vessel of earthenware or metal, used by the Greeks and Romans in libations and sacrificies.

patera
pătĕra, ae, f. [pateo], a broad , flat dish or saucer , used esp. in offerings; a libationsaucer...

A New Latin Dictionary by Charlton T. Lewis Ph.D. and Charles Short, LL. D.
patera
patera ae, f 2 PAT-, a low bowl, flattened dish, saucer, libation-saucer : paterā ad res divinas u...

An Elementary Latin Dictionary