The Collaborative International Dictionary of English v.0.48:

Sacrarium \Sa*cra"ri*um\, n.; pl. -ria. [L., fr. sacer
   sacred.]
   1. A sort of family chapel in the houses of the Romans,
      devoted to a special divinity.
      [1913 Webster]

   2. The adytum of a temple. --Gwilt.
      [1913 Webster]

   3. In a Christian church, the sanctuary.
      [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

48 Moby Thesaurus words for "sacrarium":
   Easter sepulcher, Lady chapel, adytum, ambry, apse, baptistery,
   blindstory, chancel, chantry, chapel, chapel of ease, chapel royal,
   choir, cloisters, confessional, confessionary, crypt, dagoba,
   delubrum, diaconicon, diaconicum, holy of holies, holy place, naos,
   nave, oratorium, oratory, porch, presbytery, reliquaire, reliquary,
   rood loft, rood stair, rood tower, sacellum, sacrament chapel,
   sacristy, sanctuary, sanctum, sanctum sanctorum, school chapel,
   shrine, side chapel, stupa, tope, transept, triforium, vestry