What does agglutination mean?
Agglutination is the process by which particles or cells suspended in a liquid clump together to form a mass. Its most prominent use is in immunology and haematology, where antibodies bind to antigens on the surfaces of red blood cells or bacteria, causing them to visibly cluster; this reaction underpins routine blood typing and many diagnostic tests, making it a matter of life-and-death importance in transfusion medicine. The word also has a well-established second life in linguistics, where it describes how certain languages, such as Turkish, Finnish, and Japanese, build words by attaching morphemes end-to-end with little change to each element's form. Derived from the Latin verb agglutinare, meaning 'to glue together', the term entered English in the early seventeenth century. Though technical in register, agglutination is precise, widely used across scientific disciplines, and valuable for anyone reading medical results or studying language structure.
nounThe process of joining or adhering things together into a single mass, especially the clumping of cells such as bacteria or red blood cells in response to an antibody. In linguistics, it refers to the formation of words by stringing together morphemes without significant alteration of their forms.
- Immunology/haematology: the clumping together of cells (such as red blood cells or bacteria) suspended in a fluid, typically caused by antibodies binding to antigens on the cell surface.
- Linguistics: the process of forming words by combining morphemes in which each element retains its original form and meaning, characteristic of languages like Turkish and Finnish.
"The blood sample showed clear agglutination when exposed to the test serum."
"When type A red blood cells were mixed with anti-A serum, rapid agglutination confirmed the patient's blood group."
"Turkish is often cited as a classic example of an agglutinative language, where suffixes attach to a root in orderly succession."
The plural is rare and appears mainly in technical literature referring to multiple distinct clumping reactions or instances across samples.
"Agglutinations were recorded at multiple dilutions across all tested sera."
Your blood type is determined by watching your red blood cells clump — that visible clumping is agglutination, and getting it wrong during a transfusion can be fatal.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of agglutination
Agglutination derives from the Latin verb agglutinare, meaning 'to glue or fasten together', itself formed from ad- ('to') plus glutinare ('to glue'), from gluten ('glue'). The word was borrowed into English in the early seventeenth century, initially describing the physical sticking together of substances. Its specialized senses developed later: immunologists adopted it in the late nineteenth century to describe antibody-mediated cell clumping, while linguists applied it to languages that build words from unaltered morpheme strings. Cognates sharing the same Latin root include agglutinate, conglutination, and related glue-derived terms.
Related word forms
How agglutination is actually used
Agglutination is primarily a technical term used in immunology, haematology, microbiology, and linguistics; it rarely appears in everyday conversation. In medical contexts it usually implies an observable laboratory result, so it carries a neutral, clinical connotation rather than an emotional one. The plural 'agglutinations' is uncommon and generally appears only in technical reports describing multiple distinct reactions.
Easily confused with agglutination
Coagulation is the clotting of blood into a gel via fibrin formation, whereas agglutination is the clumping of suspended cells (e.g., red blood cells) caused by antibodies binding to their surface antigens.
Aggregation is a general gathering together of particles or cells, while agglutination specifically denotes antibody-mediated clumping in immunology.