horse thistle horse-taming • horse tick · · · Info · Definitions · Synonyms · Characters · · horse thistle · · Text Common · · Latin · · Scripts 13 · · Length 3 · · Syllables Definitions · · · (noun) European annual wild lettuce having prickly stems; a troublesome weed in parts of United States. Synonyms: prickly lettuce, horse thistle, Lactuca serriola, Lactuca scariola. · · Noun Definition 1 Synonyms · · · prickly lettuce · · Synonym 1 lactuca serriola · · Synonym 2 lactuca scariola · · Synonym 3 Characters · · space U+0020 e latin small letter e U+0065 h latin small letter h U+0068 i latin small letter i U+0069 l latin small letter l U+006C o latin small letter o U+006F r latin small letter r U+0072 s latin small letter s U+0073 t latin small letter t U+0074