1rare Any of various extinct dicynodont reptiles constituting the Late Permian family Cryptodontidae, which lacked obvious teeth.
2Any of various chiefly extinct bivalve molluscs constituting the subclass or superorder Cryptodonta, the shells of which have no hinge teeth.
Of or relating to the subclass or superorder Cryptodonta of molluscs.
Mid 19th century; earliest use found in Fraser's Magazine for Town and Country. From crypto- + -odont.