Noun
(Judaism) sanctuary comprised of the innermost chamber of the Tabernacle in the temple of Solomon where the Ark of the Covenant was kept
a place of inviolable privacy
Source: WordNetWhen I would re-create myself, I seek the darkest wood, the thickest and most interminable and to the citizen, most dismal, swamp. I enter as a sacred place, a Sanctum sanctorum. There is the strength, the marrow, of Nature. Henry David Thoreau
he withdrew to his sanctum sanctorum, where the children could never go Source: Internet