from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The upper and outer element of periotic bone, in humans forming a part of the temporal bone.
from the GNU version of the Collaborative International Dictionary of English
- n. The upper and outer element of periotic bone, -- in man forming a part of the temporal bone.
from The Century Dictionary and Cyclopedia
- Literally, upon the ear: applied to a center of ossification in the mastoid region of the periotic bone.
- n. In zoology and anatomy, one of the three principal bones or separate ossifications which compose the periotic bone or auditory capsule: distinguished from the proötic and the opisthotic, and also from the pterotic when this fourth element is present.
- n. One of the outer or lateral pair of the supratemporal bones in the cranial roof of the stegocephalian Amphibia, regarded as bones of dermal origin.
- n. In ichthyology, a lateral, posterior paired bone of the cranium, usually forming a blunt projection.
epi- + Ancient Greek ear. (Wiktionary)
A third (pterotic) roofs in the tympanic cavity and antrum; while the fourth (epiotic) appears near the posterior semicircular canal and extends to form the mastoid process (Vrolik).