Blood clots developed due to venous insufficiency are called "thrombophlebitis".

"Thrombus" stands for Latin "blood clot". "Phlebitis" means "inflammation of the vein". This condition is one of complications of venous insufficiency. It results from stagnation of blood in affected veins. Thrombophlebitis is not to be mistaken with DVT, or Deep Vein Thrombosis, an independent condition resulting from combination of several factors including usually immobility, thickening of the blood (like dehydration) and injury to inner vein lining.