antibody

noun

an·​ti·​body ˈan-ti-ˌbä-dē How to pronounce antibody (audio)
: 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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Those issues included the BK virus, a flu-like polyomavirus, which resulted in both cellular and antibody rejection. Jessica Schladebeck, New York Daily News, 11 Feb. 2026 With this type, a different kind of antibody, called IgM, gets abnormally programmed. Ruth Jessen Hickman, Health, 10 Feb. 2026 In effect, the sugar acted as a beacon that guided the antibodies to their target. New Atlas, 10 Feb. 2026 Other preliminary research suggests that obesity may affect the quality and quantity of protective antibodies, which latch on to pathogens to signal attacker immune cells to target them. Lauren J. Young, Scientific American, 9 Feb. 2026 See All Example Sentences for antibody

Word History

First Known Use

1894, in the meaning defined above

Time Traveler
The first known use of antibody was in 1894

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Cite this Entry

“Antibody.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/antibody. Accessed 21 Feb. 2026.

Kids Definition

antibody

noun
an·​ti·​body ˈant-i-ˌbäd-ē How to pronounce antibody (audio)
: 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

antibody

noun
an·​ti·​body ˈant-i-ˌbäd-ē How to pronounce antibody (audio)
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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