-ˈjē noun
Etymology: I mmuno g lobulin German
1. : a class of immunoglobulins including the most common antibodies circulating in the blood that facilitate the phagocytic destruction of microorganisms foreign to the body, that bind to and activate complement, and that are the only immunoglobulins to cross over the placenta from mother to fetus
2. : an immunoglobulin of the class IgG