: 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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Pacibekitug is an antibody that targets the IL-6 pathway, although some experts maintain skepticism about the approach. Elizabeth Cooney, STAT, 31 Aug. 2026 Morawetz also notes that getting enough protein overall is also important for immune health, since the body uses it to build antibodies. Embry Roberts, Martha Stewart, 30 Aug. 2026 They’re born before antibodies – protective proteins that recognize incoming germs – can be transferred from mother to baby during the later stages of pregnancy. Brenda Goodman, CNN Money, 28 Aug. 2026 Due to antibodies from previous transfusions and a transplant, finding a compatible second kidney was nearly impossible. Maggie Menderski, Louisville Courier Journal, 28 Aug. 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 3 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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