DuckCorp Dico

Found one definition

1.                 From WordNet (r) 3.0 (2006):
                   
   
   
                   
                     
   Rh factor
       n 1: a blood group antigen possessed by Rh-positive people; if
            an Rh-negative person receives a blood transfusion from an
            Rh-positive person it can result in hemolysis and anemia
            [syn: rhesus factor, Rh factor, Rh]