||A"tri*um (&?;), n.; pl.
Atria (&?;). [L., the fore court of a Roman house.]
1. (Arch.) (a) A square hall
lighted from above, into which rooms open at one or more levels.
(b) 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.
2. (Anat.) The main part of either auricle
of the heart as distinct from the auricular appendix. Also, the whole
articular portion of the heart.
3. (Zoöl.) A cavity in ascidians into
which the intestine and generative ducts open, and which also receives the
water from the gills. See Ascidioidea.
||A"tri*um, n. (Anat.) A
cavity, entrance, or passage; as, the atrium, or atrial cavity,
in the body wall of the amphioxus; an atrium of the infundibula
of the lungs, etc.
||A"tri*um, n. (Anat.) A
cavity, entrance, or passage; as, the atrium, or atrial cavity,
in the body wall of the amphioxus; an atrium of the infundibula
of the lungs, etc.
