[ os-tee-uh-klast ]

  1. Cell Biology. one of the large multinuclear cells in growing bone concerned with the absorption of osseous tissue, as in the formation of canals.

  2. Surgery. an instrument for effecting osteoclasis.

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Origin of osteoclast

1870–75; osteo- + -clast<Greek klastós broken

Other words from osteoclast

  • os·te·o·clas·tic, adjective

Words Nearby osteoclast

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

British Dictionary definitions for osteoclast


/ (ˈɒstɪəʊˌklæst) /

  1. a surgical instrument for fracturing bone

  2. a large multinuclear cell formed in bone marrow that is associated with the normal absorption of bone

Derived forms of osteoclast

  • osteoclastic, adjective

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

Scientific definitions for osteoclast


[ ŏstē-ə-klăst′ ]

  1. A specialized bone cell that absorbs bone, allowing for the deposition of new bone and maintenance of bone strength. Osteoclasts secrete enyzmes that dissolve the matrix of old bone tissue and acids that dissolve bone salts, which contain calcium and phosphorus. Except in growing bone, the rate of bone deposition and bone absorption equal each other so that bone mass remains constant. A mass of osteoclasts absorbs bone from the outer surfaces inward for about three weeks. The osteoclasts are then converted into osteoblasts that form new bone to fill in the cavities. See also osteoblast.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.