Compact substance

Definition
noun
A type of osseous tissue consisting of closely packed osteons or haversian systems, and forms the extremely hard exterior of bones.
Supplement
Because of the closely packed osteons and multiple stacked layers with few gaps on this tissue, the compact bone is extremely hard and dense (compared with cancellous bone). These features of compact bone are vital to serve its function in providing support to the body and protecting the organs. It also provides levers for movement and store minerals (similar to cancellous bone).
Word origin: compact: L compāctus (ptp. of compingere, to shut away, bind together); bone: Middle English bon, from Old English bān.
Synonym: compact bone, cortical bone.

Compare: cancellous bone.

See also: osseous tissue.