arachidonic acid


ar·​a·​chi·​don·​ic acid ˌa-rə-kə-ˈdä-nik- How to pronounce arachidonic acid (audio)
: a liquid unsaturated fatty acid C20H32O2 that occurs in most animal fats, is a precursor of prostaglandins, and is considered essential in animal nutrition

Example Sentences

Recent Examples on the Web But too many of these fatty acids can cause inflammation when the body ultimately breaks them down into arachidonic acid, which lowers the body’s pain threshold. Sandee Lamotte, CNN, 12 Oct. 2022 According to PetMD, cats also need higher proportions of protein in their diet than dogs, as well as taurine, arachidonic acid, vitamin A and niacin. Jacob Livesay, USA TODAY, 22 July 2022 But the concentrations of vitamin A and arachidonic acid weren't even measured. Marta Zaraska,, 10 July 2019 There is arachidonic acid, an omega-6 fatty acid the body uses to make pro-inflammatory local hormones. Bryant Stamford, The Courier-Journal, 3 May 2018

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'arachidonic acid.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


New Latin Arachid-, Arachis + English -onic (as in gluconic acid)

First Known Use

1913, in the meaning defined above

Time Traveler
The first known use of arachidonic acid was in 1913

Dictionary Entries Near arachidonic acid

Cite this Entry

“Arachidonic acid.” Dictionary, Merriam-Webster, Accessed 30 Mar. 2023.

Medical Definition

arachidonic acid

ar·​a·​chi·​don·​ic acid ˌar-ə-kə-ˌdän-ik- How to pronounce arachidonic acid (audio)
: a liquid unsaturated fatty acid C20H32O2 that occurs in most animal fats, is a precursor of prostaglandins and leukotrienes, and is considered essential in animal nutrition
In a biological system for the regulation of various cell functions, arachidonic acid plays a unique role as a precursor molecule which is transformed into potent mediators with far-ranging effects.Bengt Samuelsson, Science
The prostaglandins and the leukotrienes share a common origin. They are derived, by two different enzymatic pathways, from arachidonic acid, which is formed in cells whose cell membrane has been disrupted.Paul D. Buisseret, Scientific American
Fish and other vertebrates also rely on arachidonic acid, another fat, to make compounds for managing stress and immunity.Janet Raloff, Science News
Pulmonary hypertension is thought to be due to activation and release of vasoactive mediators, including arachidonic acid metabolites, accompanied by diffuse pulmonary microvascular thrombosisHarriet Kitzman et al., The Journal of the American Medical Association
abbreviation AA, ARA

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