gamma globulin also gam·ma·glob·u·lin (gām'ə-glŏb'yə-lĭn) n.
A protein fraction of blood serum containing many antibodies that protect against bacterial and viral infectious diseases.
A solution of gamma globulin prepared from human blood and administered for passive immunization against measles, German measles, hepatitis A, and other infections.
(gām'ə-glŏb'yə-lĭn) 