Source : Webster's Revised Unabridged Dictionary (1913)

Opisthodome \O*pis"tho*dome\, n. [L. opisthodomus, Gr. ?; ?
   behind + do`mos house: cf. F. opisthodome.] (Arch.)
   A back chamber; especially, that part of the naos, or cella,
   farthest from the main entrance, sometimes having an entrance
   of its own, and often used as a treasury.