What is "glycosyl"

n. (context biochemistry English) Any functional group derived from a sugar (especially from a monosaccharide) by removal of the hemiacetal hydroxy group

A glycosyl group is a univalent free radical or substituent structure obtained by removing the hemiacetal hydroxyl group from the cyclic form of a monosaccharide and, by extension, of a lower oligosaccharide. Glycosyl also reacts with inorganic acids, such as phosphoric acid, forming an ester such as glucose 1-phosphate.