an agglutinant; (in later use) spec. an agglutinin.

An antibody or other substance that causes agglutination of cells, microorganisms, etc. (see agglutination, n. 7).

Originally: any substance producing agglutination. In later use: spec. an antigen that stimulates the production of an agglutinin.

an agglutinin that agglutinates cells of other individuals of the same species as that in which it is found.

A substance that causes agglutination of red blood cells.

an agglutinin that causes agglutination of foreign cells, esp. red blood cells of another group or from an animal of another species.

an isoagglutinin which agglutinates red blood cells.

a substance that elicits or reacts with an isoagglutinin.