n. (pl. sanctums) 1 a holy place. 2 colloq. a person's private room, study, or den. sanctum sanctorum 1 the holy of holies in the Jewish temple. 2 = sense 2 of n. 3 an inner retreat. 4 an esoteric doctrine etc.
[ L, neut. of sanctus holy, past part. of sancire consecrate: sanctorum genit. pl. in transl. of Heb. kodes hakkø dasm holy of holies ]