A square hall lighted from above, into which rooms open at
one or more levels.

An open court with a porch or gallery around three or more
sides; especially at the entrance of a basilica or other church. The
name was extended in the Middle Ages to the open churchyard or
cemetery.

The main part of either auricle of the heart as distinct
from the auricular appendix. Also, the whole articular portion of the
heart.

A cavity in ascidians into which the intestine and
generative ducts open, and which also receives the water from the
gills. See Ascidioidea.