carbohydrate glycan oligosaccharide A compound in which monosaccharide units are joined by glycosidic linkages. The term is commonly used to refer to a defined structure as opposed to a polymer of unspecified length or a homologous mixture. When the linkages are of other types the compounds are regarded as oligosaccharide analogues. LanguaL term definition: Complex carbohydrate with molecules composed of three to ten saccharide units (specifically dextrin). May be slightly sweet to the taste.