Glycoside: any one of a group ofcompounds consisting of a pyranosesugar residue, such as glucose, linkedto a noncarbohydrate residue (R) by aglycosidic bond: the hydroxyl group(–OH) on carbon-1 of the sugar is replacedby –OR. Glycosides are widelydistributed in plants; examples arethe anthocyanin pigments and thecardiac glycosides, such as digoxinand ouabain, which are used medicinallyfor their stimulant effects onthe heart.