: any of a large number of proteins of high molecular weight that are produced normally by specialized B cells after stimulation by an antigen and act specifically against the antigen in an immune response, that are produced abnormally by some cancer cells, and that typically consist of four subunits including two heavy chains and two light chains

called also immunoglobulin

Examples of antibody in a Sentence

Recent Examples on the Web
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After a first dose, people gain protective antibodies quickly and immunity levels peak within about two weeks. — Lauren J. Young, Scientific American, 18 Sep. 2026 During pregnancy, these antibodies can raise the risk of miscarriage, stillbirth, and other complications. — Julie Sharp, CBS News, 16 Sep. 2026 Some people with Sjögren’s disease do not have these antibodies. — Julie Scott, Verywell Health, 15 Sep. 2026 That post-exposure treatment typically includes a dose of an antibody medication that prevents infection, called human rabies immune globulin, and at least four doses of a rabies vaccine. — Aria Bendix, NBC news, 10 Sep. 2026 See All Example Sentences for antibody

Word History

Etymology

anti- + body entry 1, after German Antikörper

First Known Use

1894, in the meaning defined above

Time Traveler
The first known use of antibody was in 1894

Browse Nearby Words

Cite this Entry

“Antibody.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/antibody. Accessed 26 Sep. 2026.

Kids Definition

: a substance produced by special cells of the body that combines with an antigen and counteracts its effects or those of the microscopic plant or animal on which the antigen may occur

Medical Definition

plural antibodies
: any of a large number of proteins of high molecular weight that are produced normally by specialized B cells after stimulation by an antigen and act specifically against the antigen in an immune response, that are produced abnormally by some cancer cells, and that typically consist of four subunits including two heavy chains and two light chains

called also immunoglobulin

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