agglutinate

Agglutination is a process in which particles clump together due to binding interactions, typically antibodies cross-linking antigens on cell surfaces. The result is visible aggregation of cells or particles and it is central in immunology and serology. The verb agglutinate means to cause such clumping or to undergo agglutination.

In immunology, agglutination occurs when antibodies bind to antigens on different particles, cross-linking them into a lattice. Direct hemagglutination uses red blood cells; indirect agglutination uses latex or other carrier particles. Agglutination tests diagnose blood type, detect antibodies, and identify bacteria. Factors include antibody concentration, antigen density, temperature, pH, and interfering substances; the titer is the highest dilution producing visible agglutination.

Beyond biology, agglutination also refers to a linguistic process called agglutination, in which words are formed by stringing together discrete morphemes with little or no phonological change. This contrasts with fusional and isolating languages. Examples include Turkish, Finnish, and Swahili. Agglutinative morphology yields clear morpheme boundaries and precise grammatical meaning per affix.

Etymology: from Latin agglutinare, from ad "to" + glutinare "to glue."