Noun | 1. | oxyacid - any acid that contains oxygen acid - any of various water-soluble compounds having a sour taste and capable of turning litmus red and reacting with a base to form a salt hypophosphoric acid - a crystalline tetrabasic acid (H4P2O6) hypophosphorous acid, orthophosphorous acid, phosphorous acid - a clear or yellow monobasic acid (H3PO2) polyphosphoric acid - a series of oxyacids of phosphorus periodic acid - any acid of iodine that contains oxygen orthophosphoric acid, phosphoric acid - an acid used in fertilizers and soaps: H3PO4 tungstic acid - an oxyacid of tungsten (often polymeric in nature) formed by neutralizing alkaline tungstate solutions vanadic acid, vanadium pentoxide - any of various oxyacids of vanadium; known mostly in the form of its salts |