(medicine, attributive, also without cap.) Denotes a system for categorising human blood types based on the presence or absence of various antigens, especially Rhesus factor D.

A macaque monkey native to southern and southeastern Asia; Macaca mulatta. / (medicine) Alternative form of Rhesus.

(medicine) A blood group system, the second most important after the ABO system, and important in human blood transfusion, whereby blood types are classified according to the presence ("positive") or absence ("negative") of potentially over 50 antigens, of which the most commonly referenced is RhD.

A monkey, Macaca mulatta, common throughout southern Asia, that is extensively used for medical research.

The rhesus macaque, Macaca mulatta

An antigen of the Rhesus system; understood unless otherwise specified to refer to Rhesus factor D (RhD), which appears on the surface of the red blood cells of most (85%) humans. An incompatibility between the Rh-blood types of a mother and her baby may cause serious disease for the baby.

plural of rhesus monkey

plural of rhesus macaque

plural of Rhesus factor

(of blood or of a person) Lacking the RhD antigen in red blood cells.