A sarcophagus is a coffin, most commonly carved in stone, and usually displayed above ground, though it may also be buried. The word sarcophagus comes from the Greek σάρξ sarx meaning "flesh", and φαγεῖν phagein meaning "to eat"; hence sarcophagus means "flesh-eating", from the phrase lithos sarkophagos, "flesh-eating stone". The word also came to refer to a particular kind of limestone that was thought to rapidly facilitate the decomposition of the flesh of corpses contained within it due to the chemical properties of the limestone itself.