trefoil arch trefoil • trefoil knot · · · Info · Definitions · Characters · · trefoil arch · · Text Common · · Latin · · Scripts 12 · · Length 3 · · Syllables Definitions · · · (noun) a pointed arch having cusps in the intrados on either side of the apex. Synonyms: trefoil arch. · · Noun Definition 1 Characters · · space U+0020 a latin small letter a U+0061 c latin small letter c U+0063 e latin small letter e U+0065 f latin small letter f U+0066 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 t latin small letter t U+0074