What does arachidonic mean?
"Arachidonic" is a technical adjective used almost entirely in biochemistry and medicine, where its near-sole role is in the term "arachidonic acid." That substance is an essential omega-6 polyunsaturated fatty acid, twenty carbon atoms long, which the human body obtains from animal fats such as meat, eggs, and dairy, or synthesizes from linoleic acid. Stored in cell membranes, arachidonic acid is enzymatically released when tissue is injured and then converted into eicosanoids — prostaglandins, thromboxanes, and leukotrienes — that drive inflammation, fever, blood clotting, and pain signaling. This makes the word central to pharmacology: common drugs like aspirin and ibuprofen work precisely by interrupting the arachidonic acid pathway. Despite its spider-like sound, the name comes from arachis, the botanical genus of the peanut, since the related arachidic acid was first identified in that oil. Outside laboratory and clinical contexts the word has no figurative or everyday use, and readers encountering it can expect a strictly scientific setting.
adjectiveOf or relating to arachidic acid or its derivatives, especially designating arachidonic acid, an essential omega-6 fatty acid found in animal fats that the body uses to produce signaling molecules involved in inflammation.
- Relating to or derived from arachis (groundnut) oil constituents, especially arachidonic acid, a 20-carbon polyunsaturated omega-6 fatty acid released from cell membranes and metabolized into prostaglandins, leukotrienes, and other eicosanoids that mediate inflammation and immune responses.
"Inflammation triggers the release of arachidonic acid from cell membranes."
"Aspirin relieves pain by blocking the enzyme that converts arachidonic acid into prostaglandins."
"The researchers measured arachidonic acid levels in the membrane lipids of the treated cells."
Despite sounding like it belongs in a spider documentary, "arachidonic" actually comes from the Greek word for a legume — and its acid is what your body converts into the chemicals behind inflammation and pain.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of arachidonic
The adjective "arachidonic" was formed in the nineteenth century from "arachidic acid," a fatty acid first isolated from peanut (groundnut) oil, combined with the chemical suffix "-onic" indicating additional oxidation of the acid. The root traces back to Latin "arachis," itself borrowed from Greek "arakos" (or "arachos"), a name for a leguminous plant — so the word's ancestry lies with peanuts rather than spiders, despite superficial resemblance to "arachnid." It entered English scientific vocabulary alongside the systematic naming conventions of organic chemistry.
How arachidonic is actually used
Almost exclusively used in scientific, medical, and nutritional writing, nearly always as part of the phrase "arachidonic acid." It carries no informal register and no figurative use outside biochemistry.
Easily confused with arachidonic
"Arachnid" refers to eight-legged creatures like spiders and scorpions (from Greek arachne, "spider"), whereas "arachidonic" derives from arachis, the groundnut plant, and relates to a fatty acid.