Definition of patera:
(n) :
A broad, shallow dish used for drinking, primarily in ritual contexts such as libations.
(n) :
(architecture) A circular ornament, resembling a dish, often worked in relief on friezes etc.
(n) :
The caldera or crater (dish-shaped depression) atop a volcano, especially an extraterrestrial one; also used in the names of extraterrestrial volcanoes which have such a caldera.