Blood clots are a common medical condition that can be caused by a variety of factors. THROMBI, which is a seven-letter word for blood clots, are clumps of blood cells and proteins that form in the veins or arteries. Emboli, another six-letter word for blood clots, are clots that travel through the bloodstream and can cause blockages in other parts of the body. SERUM, a five-letter word for blood clots, is the liquid part of the blood that contains proteins, hormones, and other substances. Blood clots can be dangerous if they form in the wrong place or if they break off and travel to other parts of the body.