a. [ Pref. hypo- + phosphoric. ] (Chem.) Pertaining to, or derived from, or containing, phosphorus in a lower state of oxidation than in phosphoric compounds; as, hypophosphoric acid. [ 1913 Webster ]

Hypophosphoric acid (Chem.), an acid, P2H4O6, produced by the slow oxidation of moist phosphorus, and isolated only as a solution in water. It is regarded as a condensation product of one molecule of phosphoric acid with one of phosphorous acid, by partial dehydration. [ 1913 Webster ]