Sacellum

·noun A small monumental chapel in a church.

II. Sacellum ·noun An unroofed space consecrated to a divinity.

sacellum
săcellum, i, n. dim. [sacrum], a little sanctuary , i. e. a small uncovered place consecrated to a ...

A New Latin Dictionary by Charlton T. Lewis Ph.D. and Charles Short, LL. D.
sacellum
sacellum ī, n dim.sacrum, a little sanctuary, small open place consecrated to a divinity, chapel :...

An Elementary Latin Dictionary