ecchymosis

n. bruise, area of discoloration on the skin caused by a blow, contusion

A bruise, also called a contusion or ecchymosis, is a kind of injury to biological tissue in which the capillaries are damaged, allowing blood to seep into the surrounding tissue. It is usually caused by blunt impact. Bruises often induce pain but are not normally dangerous. Sometimes bruises can be serious, leading to other more life threatening forms of hematoma, or can be associated with serious injuries, including fractures and internal bleeding. Minor bruises may be easily recognized, in people with light skin color, by their characteristic blue or purple appearance in the days following the injury.
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Ecchymosis /ec·chy·mo·sis/ pl. ecchymo´ses [Gr.] a small hemorrhagic spot in the skin or a mucous membrane, larger than a petechia, forming a [more]Ecchymosis - Community and Resources

Noun
1. the purple or black-and-blue area resulting from a bruise
(hypernym) bruise, contusion
2. the escape of blood from ruptured blood vessels into the surrounding tissue to form a purple or black-and-blue spot on the skin
(hypernym) organic process, biological process

(n.)
A livid or black and blue spot, produced by the extravasation or effusion of blood into the areolar tissue from a contusion.