from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. The mastoid process.
  • adj. Of or relating to the mastoid process.
  • adj. Shaped like a breast or nipple.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • adj. Of or relating to the mastoid process.
  • n. The mastoid process.
  • adj. Shaped like a breast or nipple.

from the GNU version of the Collaborative International Dictionary of English

  • adj. Resembling the nipple or the breast; -- applied specifically to a process of the temporal bone behind the ear.
  • adj. Pertaining to, or in the region of, the mastoid process; mastoidal.

from The Century Dictionary and Cyclopedia

  • Teat-like; shaped like a nipple: specifically applied in anatomy to a part or process of the temporal bone, from its shape in man. See below.
  • n. The mastoid part or process of the temporal bone: in adult man, a conical nipplelike bony prominence below and behind the orifice of the ear, to which the sternoclido-mastoid, trachelomastoid, digastric, and other muscles are attached, and which is grooved for the passage of the occipital artery.
  • n. A distinct bone of the skull of some of the lower vertebrates, regarded by Owen as homologous with the mammalian mastoid.
  • n. Same as pterotic.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • adj. relating to or resembling a nipple
  • n. process of the temporal bone behind the ear at the base of the skull
  • adj. of or relating to or in the region of the mastoid process


New Latin mastoīdēs, nipple-like, mastoid (from its shape), from Greek mastoeidēs : mastos, breast + -oeidēs, -oid.
(American Heritage® Dictionary of the English Language, Fourth Edition)
From Ancient Greek μάσταξ (mastax, "jaws, what chews") (Wiktionary)
From Ancient Greek μαστός (mastos, "breast") (Wiktionary)


  • It is perforated by numerous foramina; one of these, of large size, situated near the posterior border, is termed the mastoid foramen; it transmits a vein to the transverse sinus and a small branch of the occipital artery to the dura mater.

    II. Osteology. 5a. 4. The Temporal Bone

  • The Auricular Branch (ramus auricularis) supplies the back of the concha and frequently gives off a branch, which enters the skull through the mastoid foramen and supplies the dura mater, the diploë, and the mastoid cells; this latter branch sometimes arises from the occipital artery, and is then known as the mastoid branch.

    VI. The Arteries. 3a. 2. The External Carotid Artery

  • The mastoid is the small bone directly behind the ear.

    eHow - Health How To's

  • And the sharpness of this cry is a shard of green glass that is spun long with razor thinness, and it enters those for whom it is calling just behind the left ear, lodging in the hollow between the mandible and mastoid, a reminder, a pact, and one that has been made with the scent of blood heavy in the air.

    Between Expectations

  • It's about the size of an MP3 player and is connected to the mastoid bone behind the ear using a sensor cable, which sends electric pulses into the vestibular system.

    Dr. Michael J. Breus: Insomniacs: Rock Yourself to Sleep

  • This will cause flattening of the back of the head on the affected side, protrusion of the mastoid bone, and posterior positioning of the affected ear.

    The Beauty of Love

  • He was an only child, irreversibly Italian in a WASP world, scarred by forceps and acne and a mastoid operation, so skinny he nearly disappeared behind his microphone.

    When Sinatra had the world on a string

  • Another had smashed through the mastoid bone behind his right ear and atomized into tiny fragments that angled through his brain.

    Bobby's Last, Longest Day

  • Two weeks later, I was diagnosed with rare tumors in my ear and mastoid.

    Babes with a Beatitude

  • Noguchi stated that the shot that killed RFK “had entered through the mastoid bone, an inch behind the right ear and had traveled upward to sever the branches of the superior cerebral artery.”

    40 Years Since RFK Assassination, Mounting Evidence of CIA Involvement


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