What does osteoclast mean?
An osteoclast is a specialized cell that breaks down bone by resorbing its mineral and organic matrix. This process is essential for normal skeletal remodeling, calcium regulation, and the repair of bone, although excessive osteoclast activity can contribute to osteoporosis and other conditions involving bone loss. Osteoclasts are large cells formed by the fusion of precursor cells, and they work in close balance with osteoblasts, the cells responsible for forming new bone. In medicine and biological research, the term most often refers to the cell itself; more specialized surgical usage can refer to an instrument or technique for fracturing or reshaping bone. Its contrasting term, osteoblast, is useful for remembering the distinction between bone breakdown and bone formation.
nounA large multinucleated cell that breaks down and resorbs bone, helping regulate bone renewal and calcium balance. In some medical contexts, the term can also refer to an instrument or procedure used to fracture or remodel bone.
- A large multinucleated cell that resorbs bone by dissolving and breaking down its mineralized matrix.
- A surgical instrument or technique used to fracture or reshape bone.
"The researchers inhibited osteoclast activity to reduce the breakdown of bone in the affected patients."
"Increased osteoclast activity contributed to the loss of density in her bones."
"The osteoclast carefully separated the fragments before the surgeon repositioned them."
The standard plural is used when discussing multiple bone-resorbing cells, as in “osteoclasts were active at the bone surface.”
"The imaging showed unusually active osteoclasts along the damaged bone."
Without osteoclasts, old bone could not be efficiently cleared away; without osteoblasts, the resulting gap could not be reliably rebuilt.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does osteoclast come from?
The word was formed in the 19th century from Greek osteon, meaning “bone,” and klastos, meaning “broken.” The same Greek elements underlie related medical terms such as osteoblast and osteoporosis. Its name reflects the cell's principal function: breaking down bone during skeletal remodeling.
Related word forms
How osteoclast is actually used
The cellular sense is standard in physiology, pharmacology, and bone research. The second sense is specialized and chiefly used in surgical or historical medical literature.
Easily confused with osteoclast
Osteoclasts break down bone, whereas osteoblasts are cells that help build new bone.