humic acid humic • humic shale · · · Info · Definitions · Characters · · humic acid · · Text Common · · Latin · · Scripts 10 · · Length 4 · · Syllables Definitions · · · (noun) a dark brown humic substance that is soluble in water only at pH values greater than 2. Synonyms: humic acid. Example: "The half-life of humic acid is measured in centuries." · · 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 m latin small letter m U+006D u latin small letter u U+0075