[stur-nuh m]
noun, plural ster·na [stur-nuh] /ˈstɜr nə/, ster·nums.
  1. Anatomy, Zoology. a bone or series of bones extending along the middle line of the ventral portion of the body of most vertebrates, consisting in humans of a flat, narrow bone connected with the clavicles and the true ribs; breastbone.
  2. the ventral surface of a body segment of an arthropod.

Origin of sternum

1660–70; < New Latin < Greek stérnon chest, breastbone Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

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British Dictionary definitions for sternum


noun plural -na (-nə) or -nums
  1. (in man) a long flat vertical bone, situated in front of the thorax, to which are attached the collarbone and the first seven pairs of ribsNontechnical name: breastbone
  2. the corresponding part in many other vertebrates
  3. a cuticular plate covering the ventral surface of a body segment of an arthropodCompare tergum
Derived Formssternal, adjective

Word Origin for sternum

C17: via New Latin from Greek sternon breastbone
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 sternum

1660s, from Greek sternon "chest, breast, breastbone" (in Homer, only of males), from PIE *stre-to- "to stretch, extend," from a root meaning "flat surface," related to stornynai "to spread out" (see structure (n.)), on the notion of the chest as broad and flat, as opposed to the neck.

Online Etymology Dictionary, © 2010 Douglas Harper

sternum in Medicine


n. pl. ster•nums
  1. A long flat bone, articulating with the cartilages of the first seven ribs and with the clavicle, forming the middle part of the anterior wall of the thorax, and consisting of the corpus, manubrium, and xiphoid process.breastbone
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

sternum in Science


  1. A long, flat bone located in the center of the chest, serving as a support for the collarbone and ribs. Also called breastbone See more at skeleton.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.