What exactly is venous thrombosis?

Blood clot in vein: Venous thrombosis can be in veins close to the skin, hence superficial thrombosis or thrombophlebitis, appearing as a painful cord, red, with heat. It can occur in the deep veins, hence deep venous thrombophlebitis (dvt), and there is often pain, swelling in the calf/thigh muscle. It can occur in the veins of the brain, hence cerebral venous thrombosis.

Blood clots: Thrombosis is clotting and when it is in the vein it is called venous thrombosis...If it is inflamed it si called throbophlebitis...The causes are several from inherited coagulation disorders to trauma to low blood flow to obstruction to the proximal vein to name a few.

A clot: That has occurred in a vein. Either a superficial vein or deep vein.

Blood clot in vein: Venous = vein and thrombosis = clot. So venous thrombosis is a blood clot in any vein in the body. It can be in a superficial vein close to the surface (superficial venous thrombosis) or involve a deep vein (deep venous thrombosis). Whether deep or superficial & its location will determine the best treatment options. Consults w/ a vascular surgeon (specialists in blood clots), or a hematologist