Niagara niacin • Niagaran · · · Info · Definitions · Characters · · Niagara · · Text Latin · · Script 7 · · Length Definitions · · · (noun) waterfall in Canada is the Horseshoe Falls; in the United States it is the American Falls. Synonyms: Niagara Falls. · · Noun Definition 1 (noun) a river flowing from Lake Erie into Lake Ontario; forms boundary between Ontario and New York. Synonyms: Niagara River. · · Noun Definition 2 Characters · · N latin capital letter n U+004E a latin small letter a U+0061 g latin small letter g U+0067 i latin small letter i U+0069 r latin small letter r U+0072