Dahlia \Dah"lia\ (d[aum]l"y[.a] or d[=a]l"y[.a]; 277, 106), n.; pl. {Dahlias}. [Named after Andrew Dahl a Swedish botanist.] (Bot.) A genus of plants native to Mexico and Central America, of the order Composit[ae]; also, any plant or flower of the genus. The numerous varieties of cultivated dahlias bear conspicuous flowers which differ in color.