ABO system

noun

1. Physiology. a classification of human blood based on the presence on the surface of red blood cells of one or both of two specific antigens, designated A and B, or their absence, designated O: every person has one of four possible inherited blood types, A, B, AB, or O, and has antibodies circulating in the blood that clump with any antigen that is not of that type, persons with type O thus being able to donate blood devoid of the antigens for transfusion to types A, B, and AB but able to receive only blood of type O. : ABO

ABO system

noun

1. a system for classifying human blood on the basis of the presence or absence of two antigens on the red cell membrane: there are four such blood types (A, B, AB, and O)

ABO system

/ ā′bē-ō′ /

1. A classification system for human blood that identifies four major blood types based on the presence or absence of two antigens, A and B, on red blood cells. The four blood types (A, B, AB, and O, in which O designates blood that lacks both antigens) are important in determining the compatibility of blood for transfusion.

Word History and Origins

Origin of ABO system¹

First recorded in 1940–45