Webster's Revised Unabridged Dictionary · 1913

Reredos

Reredos (r?r"d?s) , noun

[From rear + French dos back, Latin dorsum. Compare Dorsal.]

(a)
(Architecture) A screen or partition wall behind an altar.
(b)
(Architecture) The back of a fireplace.
(c)
(Architecture) The open hearth, upon which fires were lighted, immediately under the louver, in the center of ancient halls. — Fairholt