Final answer:
An embolus is the term for a free-floating thrombus in the bloodstream. It can cause life-threatening conditions like heart attacks, strokes, or pulmonary embolisms if it obstructs an artery in a crucial organ.
Step-by-step explanation:
The term used to describe a free-floating thrombus in the bloodstream is an embolus. A thrombus is an aggregation of platelets, erythrocytes, and white blood cells (WBCs) typically trapped within a mass of fibrin strands that form due to certain conditions such as thrombosis or thrombocytosis. When a thrombus detaches from the vessel wall, it becomes an embolus, which can travel through the bloodstream and has the potential to cause serious medical emergencies like a heart attack, stroke, or pulmonary embolism when it lodges in a vital organ's artery obstructing blood flow.