The Latin phrase sanctum sanctorum is a translation of the Hebrew term קֹדֶשׁ הַקֳּדָשִׁים (Qṓḏeš HaQŏḏāšîm), literally meaning Holy of Holies, which generally refers in Latin texts to the holiest place of the Ancient Israelites, inside the Tabernacle and later inside the Temple in Jerusalem, but the term also has some derivative use in application to imitations of the Tabernacle in church architecture.

The plural form sancta sanctorum is also used, arguably as a synecdoche, referring to the holy relics contained in the sanctuary. The Vulgate translation of the Bible uses sancta sanctorum for the Holy of Holies. Hence the derivative usage to denote the Sancta Sanctorum chapel in the complex of the Archbasilica of Saint John Lateran, Rome.

In Hinduism, a temple's innermost part where the Murti of the deity is kept forms the Garbha griha, also referred to as a sanctum sanctorum.