Words related to atrium

*āter-, Proto-Indo-European root meaning "fire." It forms all or part of: atrabiliary; atrabilious; atrium; atrocious.

It is the hypothetical source of/evidence for its existence is provided by: Old Persian atar "fire;" Latin ater "black" ("blackened by fire"), atrox "frightful" ("of fiery or threatening appearance").
aerie (n.)
"eagle's nest," 1580s (attested in Anglo-Latin from early 13c.), from Old French aire "nest," Medieval Latin area "nest of a bird of prey" (12c.), perhaps from Latin area "level ground, garden bed" [Littré], though some doubt this [Klein]. Another theory connects it to atrium. Formerly spelled eyrie (1660s) on the mistaken assumption that it derived from Middle English ey "egg."
atria (n.)
classical plural of atrium.
atrial (adj.)
by 1860 in the medical sense "pertaining to one of the atria of the heart," from atrium + -al (1).