Ossuarium is a term typically used to describe a place of burial or a container that holds human bones. If you're looking for synonyms to express similar meanings, there are several words to choose from. One such word is crypt, which refers to an underground room or vault typically used for burials. Another synonym for ossuarium is charnel house, which describes a building or room used for storing human bones. Sepulcher is another word that can be used to express the same concept, referring to a burial vault or tomb. Other synonyms for ossuarium include catacomb, mausoleum, and tomb.