orthophosphoric acid orthophosphoric • orthophosphorous acid · · · Info · Definitions · Synonyms · Characters · · orthophosphoric acid · · Text Common · · Latin · · Scripts 20 · · Length 7 · · Syllables Definitions · · · (noun) an acid used in fertilizers and soaps: H3PO4. Synonyms: phosphoric acid, orthophosphoric acid. · · Noun Definition 1 Synonyms · · · phosphoric acid · · Synonym 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 t latin small letter t U+0074