An acid of unpleasant odor occurring in butter, cod liver oil, sweat, and many other substances. It exists in two forms: normal b. (also written as n-b.), butanoic acid, which occurs in combination with glycerol in cow's butter; and isobutyric acid, 2-methylpropanoic acid, one of the intermediates in valine catabolism, found in combination with glycerol in croton oil and elsewhere.
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butyric acid n either of two isomeric fatty acids C4H8O2:
a) a normal acid of unpleasant odor found in rancid butter and in perspiration
b) ISOBUTYRIC ACID
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bu·tyr·ic ac·id (bu-tērґik) 1. any four-carbon carboxylic acid, either n-butyric acid or isobutyric acid. 2. n-butyric acid, a saturated four-carbon fatty acid occurring in butter, particularly rancid butter, and in much animal fat. Systematic name: butanoic acid.Medical dictionary. 2011.