gly·co·side (gl??k?-s?d?)n. Any of a group of organic compounds, occurring abundantly in plants, that yield a sugar and one or more nonsugar substances on hydrolysis.[glycose, a monosaccharide (variant of glucose) + -ide.]gly?co·sid?ic (-s?d??k) adj.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.glycoside (??la?k???sa?d) n (Chemistry) any of a group of substances, such as digitoxin, derived from monosaccharides by replacing the hydroxyl group by another group. Many are important medicinal drugs. See also glucoside glycosidic adjCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014gly?co?side (?gla? k??sa?d) n. any of the class of compounds that yield a sugar and an aglycon upon hydrolysis. [1925?30; alter. of glucoside, with y from glyco-] gly`co?sid?ic (-?s?d ?k) adj. Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.