What is a localized swelling filled with blood due to a broken blood vessel known as?

A localized swelling filled with blood due to a broken blood vessel is accurately referred to as a hematoma. This condition occurs when blood leaks out of a damaged blood vessel into the surrounding tissues, leading to a collection of blood that forms a swollen area. Hematomas can occur in various parts of the body and are often the result of trauma, although they can also develop in the absence of clear injury due to conditions like clotting disorders.

In contrast to a hematoma, a contusion is characterized by bleeding into the skin and underlying tissues but does not form a distinct collection of blood like a hematoma. Edema refers to the accumulation of fluid in the interstitial spaces of tissues, resulting in swelling, but it is not specifically blood. Hemorrhage describes the loss of blood, either externally or internally, from the circulatory system, but does not specifically denote the localized nature or swelling characteristic of a hematoma. Thus, the definition aligns best with a hematoma.