Synanthrose \Syn*an"throse"\, n. [From NL. Synanther[ae] the Composit[ae]; Gr. sy`n with + ? blooming.] (Chem.) A variety of sugar, isomeric with sucrose, found in the tubers of the Jerusalem artichoke ({Helianthus tuberosus}), in the dahlia, and other Composit[ae].