1. The act or process of agglutinating; adhesion of distinct parts.

2. A clumped mass of material formed by agglutination. Also called agglutinate.

3. Biology The clumping together of cells or particles, especially bacteria or red blood cells, usually in the presence of a specific antibody or other substance.

4. Linguistics The formation of words from morphemes that retain their original forms and meanings with little change during the combination process.