adjective Anatomy.

of or relating to the mastoid process.
resembling a breast or nipple.


Origin of mastoid

1725–35; < New Latin mastoīdēs < Greek mastoeidḗs. See masto-, -oid
Related formsin·ter·mas·toid, adjectivepost·mas·toid, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for mastoid

Historical Examples of mastoid

British Dictionary definitions for mastoid



shaped like a nipple or breast
designating or relating to a nipple-like process of the temporal bone behind the ear


the mastoid process
informal mastoiditis
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for mastoid

"breast-shaped, resembling a breast or nipple," 1732, from Greek mastoeides "resembling a breast," from mastos "(woman's) breast" (see masto-) + -oeides "like," from eidos "form, shape" (see -oid). As a noun, 1800, from the adjective.

Online Etymology Dictionary, © 2010 Douglas Harper

mastoid in Medicine




The mastoid process.


Of or relating to the mastoid process, antrum, or sinuses.
Shaped like a breast or nipple.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.