blood type

Short definition from Wiktionary

Noun

1. 1
   Any classification of human blood by the presence or absence of various antigens in a person’s red blood cells.
2. 2
   Any classification of human blood by the presence or absence of various antigens in a person’s red blood cells: One of eight possible classifications within the ABO and Rh blood group systems, commonly used to determine a person's compatibility for blood transfusion.