What defines a blood clot that forms inside a blood vessel or heart cavity?

A blood clot that forms inside a blood vessel or heart cavity is specifically referred to as a thrombus. Thrombus formation is a key aspect of hemostasis, the process that prevents excessive bleeding when blood vessels are injured. When a thrombus forms, it can restrict or block blood flow, potentially leading to serious conditions, such as heart attacks or strokes, if it occurs in critical areas.

While "thrombosis" refers to the formation of a thrombus and is related to the process, it is not the name of the clot itself. An "embolus" describes a piece of a thrombus or other material that travels through the bloodstream and can cause occlusion elsewhere, while "attenuation" refers to the reduction in force or effect, which is not relevant in this context. Therefore, the term most accurately defining a blood clot formed within a blood vessel or heart cavity is indeed thrombus.