Black blue mark often refers to a bruise that appears on the skin due to trauma or injury. There are several synonyms that can be used to describe this type of mark, such as contusion, ecchymosis, hematoma, or discoloration. A contusion is a type of injury that causes the skin to turn red or purple, while ecchymosis is the medical term for a bruise that appears on the skin due to bleeding under the skin's surface. Hematoma is another term used to describe a localized collection of blood outside the blood vessels. Lastly, discoloration refers to any type of change in skin color due to injury or medical condition.