It usually refers to the flow of blood, but it can also be used for other fluids like mucus or pus.
Here are some examples:
* Hemorrhage: Excessive bleeding.
* Menorrhagia: Excessive menstrual bleeding.
* Rhinorrhagia: Excessive nasal bleeding.
* Cerebrospinal fluid rhinorrhea: Leakage of cerebrospinal fluid from the nose.
The suffix "-rrhea" is closely related to "-rrhage" and means "flow or discharge", but it generally doesn't have the implication of being excessive.