(organic chemistry) a white crystalline dicarboxylic acid, CH₂(COOH)₂, used in making barbiturates

(organic chemistry) an unsaturated organic dicarboxylic acid, HOOCCH=CHCOOH, the geometric isomer of fumaric acid; it is found in unripe fruit, and is used industrially in the production of polyester resins

(organic chemistry) an auxin plant hormone, synthesized in leaves, that stimulates growth, especially in the presence of ethylene

(biochemistry) A nonessential amino acid, α-amino-glutaric acid, occurring widely in animal and plant tissues; the salt, monosodium glutamate is used as a flavour-enhancing seasoning.

(chemistry, obsolete) Hydrocyanic acid.

(music) A style of music from the early rave scene in the UK.

(inorganic chemistry) A weak acid, HNO₂, known only in solution, or as its salts and esters, the nitrites; it has a linear structure, H-O-N=O

(biochemistry, organic chemistry) A polycyclic heterocyclic carboxylic acid, one of the vitamin B complex, essential for cell growth and reproduction

(organic chemistry) octadecanoic acid; the most common saturated fatty acid; it is found in all animal and most vegetable oils and fats; it is used in the manufacture of soap etc.

(organic chemistry) An unsaturated fatty acid, having 18 carbon atoms and one double bond, found in olive oil and very many other vegetable and animal oils and fats; it is used for making soap, cosmetics etc.