A molecular entity or chemical species capable of donating a hydron (proton) (see Brønsted acid) or capable of forming a covalent bond with an electron pair (see Lewis acid).
See also: hard acid, carboxylic acids, oxoacids, sulfonic acids
Source:
PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1081 (https://doi.org/10.1351/pac199466051077)
See also:
PAC, 1990, 62, 2167. 'Glossary of atmospheric chemistry terms (Recommendations 1990)' on page 2170 (https://doi.org/10.1351/pac199062112167)