Black eye (i.e. circumorbital haematoma or hematoma)
A hematoma, or haematoma, is a collection of blood, generally the result of hemorrhage, or, more specifically, internal bleeding. Hematomas exist as bruises (ecchymoses), but can also develop in organs.
A black eye (periorbital hematoma) is bruising around the eye commonly due to an injury to the face rather than an eye injury. The name is given due to the color of bruising.