an agglutinogen commonly found in human blood: it may cause a haemolytic reaction, esp during pregnancy or following transfusion of blood that does not contain this agglutinogen
Full name: rhesus factor
Word origin
C20: named after the rhesus monkey, in which it was first discovered
Rh factor in American English
(ˈɑrˈeɪtʃ)
US
a group of antigens, determined by heredity and usually present in human red blood cells, which may cause hemolytic reactions during pregnancy or after transfusionof blood containing this factor into someone lacking it
see also Rh positive, Rh negative
Word origin
rhesus: from having been discovered first in the blood of rhesus monkeys