litmus litiscontestational • Litopterna · · · Info · Definitions · Synonyms · Characters · · litmus · · Text Latin · · Script 6 · · Length Definitions · · · (noun) a coloring material (obtained from lichens) that turns red in acid solutions and blue in alkaline solutions; used as a very rough acid-base indicator. Synonyms: litmus test. · · Noun Definition 1 Synonyms · · · litmus test · · Synonym 1 Characters · · i latin small letter i U+0069 l latin small letter l U+006C m latin small letter m U+006D s latin small letter s U+0073 t latin small letter t U+0074 u latin small letter u U+0075