Sanctum sanctorum
The Latin phrase sanctum sanctorum is a translation of the Hebrew term קֹדֶשׁ הַקֳּדָשִׁים, literally meaning Holy of Holies, in Latin texts, this generally refers to the holiest place of the Ancient Israelites, inside the Tabernacle and later inside the Temple in Jerusalem. However, 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 in the sanctuary. The Vulgate translation of the Bible uses sancta sanctorum for the Holy of Holies. Hence, the derivative usage denotes the Sancta Sanctorum chapel in the complex of the Archbasilica of Saint John Lateran, Rome.
The Garbhagriha in Hindu temples has been compared to a sanctum sanctorum, and is sometimes translated into English as such.
Etymology
The Latin word sanctum is the neuter form of the adjective "holy," and sanctorum is its genitive plural. Thus, the term sanctum sanctorum literally means "the holy of the holy," replicating in Latin the Hebrew construction for the superlative, with the intended meaning "the holiest ."Use of the term in modern languages
The Latin word sanctum may be used in English, following Latin, for "a holy place" or a sanctuary, as in the novel Jane Eyre, which refers to "the sanctum of the schoolroom."Romance languages tend to use sancta sanctorum, treating it as masculine and singular. E.g., the Spanish dictionary of the Real Academia Española admits sanctasanctórum as a derivative Spanish noun denoting both the Holy of Holies in the Temple in Jerusalem, any secluded and mysterious place and something that a person holds in the highest esteem.
The term is still often used by Indian writers for the garbhagriha or inner shrine chamber in Hindu temple architecture, after being introduced by British writers in the 19th century.