Haematic is an adjective that refers to anything related to or containing blood. It is often used in medical contexts, but can also be used to describe literary works or visual art. Synonyms for haematic include sanguine, bloody, hematopoietic, erythrocytic, hemal, and hemoglobin. Sanguine is often used in a broader sense to denote a positive or optimistic outlook, but can also be used as a synonym for haematic. Bloody and hematopoietic are more specific and refer to blood or blood-forming processes. Erythrocytic is a more technical term that specifically describes red blood cells, while hemal and hemoglobin relate to the circulatory system in general.