hypophosphoric acid hypophosphoric • hypophosphorous · · · Info · Definitions · Characters · · hypophosphoric acid · · Text Common · · Latin · · Scripts 19 · · Length 7 · · Syllables Definitions · · · (noun) a crystalline tetrabasic acid (H4P2O6). Synonyms: hypophosphoric acid. · · Noun Definition 1 Characters · · space U+0020 a latin small letter a U+0061 c latin small letter c U+0063 d latin small letter d U+0064 h latin small letter h U+0068 i latin small letter i U+0069 o latin small letter o U+006F p latin small letter p U+0070 r latin small letter r U+0072 s latin small letter s U+0073 y latin small letter y U+0079