mastoid bone
noun
The posterior portion of the temporal bone in humans and other mammals, which includes the mastoid process. Formerly also: †designating any of several bones of the skull in other vertebrates, regarded as homologous with this part of the temporal bone (obsolete ). Also (chiefly in Medicine ): = mastoid process.
Origin
Mid 19th century; earliest use found in Robert Edmond Grant (1793–1874), comparative anatomist and transmutationist.