flat arch flat • flat-armed · · · Info · Definitions · Synonyms · Characters · · flat arch · · Text Common · · Latin · · Scripts 9 · · Length 2 · · Syllables Definitions · · · (noun) an arch with mutually supporting voussoirs that has a straight horizontal extrados and intrados. Synonyms: flat arch, straight arch. · · Noun Definition 1 Synonyms · · · straight arch · · Synonym 1 Characters · · space U+0020 a latin small letter a U+0061 c latin small letter c U+0063 f latin small letter f U+0066 h latin small letter h U+0068 l latin small letter l U+006C r latin small letter r U+0072 t latin small letter t U+0074