Haem

Part of speech: noun

Definitions

1. A prefix indicating a relation to blood or blood components; referring to substances, processes, or conditions associated with hemoglobin or blood coagulation; indicating the presence of iron-containing compounds within biological systems
2. Pertaining to blood or its constituents, often used in medical or scientific terminology ; indicating various blood-related conditions or treatments ; suggesting the iron-containing aspect of biological molecules such as hemoglobin
3. Relating to blood or hematology, used in context of blood disorders ; associated with elements or compounds having iron in their structure ; denoting aspects of physiological processes involving blood circulation or oxygen transport

Etymology: Haem is the British, Australian and Commonwealth spelling of "heme", and its origin runs backwards. Chemists did not build it from a Greek root for blood. They first named the larger molecule, hemoglobin, the protein that carries oxygen in red blood cells, and then split off its iron-bearing part and named that after the whole. "Heme" is a back-formation: a shorter word cut out of a longer one that already existed. The name therefore points to blood, since the group sits inside hemoglobin, and "hemoglobin" itself combines "hemo-", from the Greek "haima" meaning blood, with "globin", the protein portion of the molecule. Hemoglobin is the longer word, and the shorter one came out of it.

Synonyms: heme, hemoglobin, iron porphyrin, blood pigment, heme group