deep vein thrombosis (EFO_0003907, an Experimental Factor Ontology id) is the formation or presence of a blood clot (THROMBUS) within a deep vein in the lower extremity. Also known as: DVT, Deep Vein Thromboses, Deep Venous Thromboses, Deep Venous Thrombosis, Deep-Vein Thromboses, Deep-Vein Thrombosis, Deep-Venous Thromboses, Deep-Venous Thrombosis.