(organic chemistry) A clear colourless organic acid, CH₃COOH, formed by the bacterial oxidation of ethanol through acetic fermentation; it is used as a solvent and has very many industrial applications; it is the major acidic component of vinegar.

(inorganic chemistry) An unstable acid, H₂S₂O₂, only known in solution, used as a reducing agent; its salts are hyposulfites).

(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

(obsolete, inorganic chemistry) Hydrochloric acid. / A low grade, industrial grade or impure form of hydrochloric acid, often containing traces of iron.

(organic chemistry) An unsaturated fatty acid cis-6-octadecenoic acid found in many members of the family Apiaceae (e.g. parsley seed oil); it is a positional isomer of oleic acid, the double bond being in position 6 instead of 9.

(chemistry) A supposed acid formed from osmium tetroxide but known only as osmate salts.

(organic chemistry) The compound with the formula CH₃CH₂COOH, a naturally occurring carboxylic acid with a pungent odor.

A colourless liquid with a sharp unpleasant odour; produced by the bacterial breakdown of fatty acids and therefore found in sweat and some cheese.

(organic chemistry) Synonym of pyrogallol