A fracture is a break in a solid item that causes discontinuity without the substance actually separating into two or more pieces. (If the substance separated into pieces, the event would likely be called breaking or shattering.)

The word fracture is most often applied to bones of living creatures, or to crystals or crystalline materials, such as gemstones or metal. Depending on the substance which is fractured, a fracture reduces strength (most substances) or inhibits transmission of light (optical crystals).

A fractured bone in a living person is treated by immobilization with a plaster or fiberglass cast, and in some cases surgical screws, plates and wires to supplement a cast. Operative methods of treating fractures have their own risks and benefits and should be carefully considered before embarking on the intervention.

See also: fibrocartilage callus