sanctum sanctorum

noun

1. the holy of holies of the Biblical tabernacle and the Temple in Jerusalem.
2. sanctum(def 2).

noun

1. Bible another term for the holy of holies
2. often facetious an especially private place

Latin for “holy of holies.” The place in the Jewish temple in Jerusalem (see also Jerusalem) where the Ark of the Covenant was kept. By extension, a sacred and private place.