osteoclast

noun

os·​te·​o·​clast ˈä-stē-ə-ˌklast 

: any of the large multinucleate cells closely associated with areas of bone resorption

osteoclastic

ˌä-stē-ə-ˈkla-stik 

adjective

Examples of osteoclast in a Sentence

Recent Examples on the Web

Bone formation is coupled with bone resorption, as osteoblasts build bone at the same rate that osteoclasts resorb bone. —Lorena Meouchi, Vogue, 6 Mar. 2025

Throughout life, our bone tissue is maintained by bone-building osteoblasts working in harmony with counterpart cells called osteoclasts, which break down old bone that needs replacing. —Jolene Edgar, Allure, 11 Feb. 2025

Manganese is also involved in skeletal health by regulating the activity of osteoblasts and osteoclasts, specialized cells that build up and break down bone tissue, respectively.6 Manganese is also required to produce collagen, a major component of bone tissue and your skin. —Jillian Kubala, Health, 5 Feb. 2025

The disease occurs when there's an imbalance between a person's osteoblasts – which are bone-building cells – and their osteoclasts, which are bone-degrading cells. —Ben Coxworth, New Atlas, 2 Feb. 2025

In modern skeletons, tiny blood vessels that burrow into the bone’s hard matrix provide an inroad for cells called osteoclasts to eat away old bone and for cells called osteoblasts to begin making new bone. —Byelizabeth Pennisi, science.org, 10 Jan. 2025

Having narrowed down the likely culprit, the researchers sought to target and remove the senescent osteoclasts. —William A. Haseltine, Forbes, 11 Dec. 2023

But in certain situations, the osteoclasts ended up misbehaving, leading to excessive pore formation in the endplates of the spine. —William A. Haseltine, Forbes, 11 Dec. 2023

Meanwhile, in the marrow cavity, osteoclasts are eroding the bone that was deposited early in life, and other cells are making secondary bone tissue along the perimeter of the cavity or invading the cortex (outer layer) of the remaining bone to remodel it. —Kevin Padian, Scientific American, 1 May 2014

Word History

Etymology

borrowed from German Ostoklasten (plural), from Greek ostoklástēs "bearded vulture," literally "bone breaker," from its habit of dropping bones from a height in order to crack them (from osto-, variant of osteo- osteo- + -klastēs, derivative, with the agent suffix -tēs, from the base of kláō, klân "to break off, break in pieces") + German -en, plural suffix — more at clastic

Note: The term was introduced by the Swiss-born anatomist and histologist Albert Kölliker (1817-1905) in "Die Verbreitung und Bedeutung der vielkernigen Zellen der Knochen und Zähne," "vorgetragen in der Sitzung am 2. März 1872," Verhandlungen der Physikalisch-Medicinischer Gesellschaft zu Würzburg, Neue Folge, 2. Band (1872), p. 243. Kölliker states that he named the cells Ostoklasten ("Knochenbrecher" [bone-breakers]) because they dissolved the tissue of bones and teeth. The name Ostoklasten was quickly changed to the more regular Osteoklasten, borrowed into English as osteoclasts.

First Known Use

1872, in the meaning defined above

Rhymes for osteoclast

• enthusiast
• iconoclast
• osteoblast
• aghast
• amassed
• biassed
• broadcast
• bypassed
• downcast
• forecast
• foremast
• harassed

Medical Definition

osteoclast

noun

os·​teo·​clast ˈäs-tē-ə-ˌklast 

1

: any of the large multinucleate cells closely associated with areas of bone resorption (as in a fracture that is healing) compare chondroclast

2

: an instrument for performing osteoclasis

osteoclastic

ˌäs-tē-ə-ˈklas-tik 

adjective