xy·lose (z??l?s?)n. A crystalline monosaccharide, C5H10O5, that is a component of most hemicelluloses in plants. Also called wood sugar.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.xylose (?za?l??z; -l??s) n (Elements & Compounds) a white crystalline dextrorotatory sugar found in the form of xylan in wood and straw. It is extracted by hydrolysis with acids and used in dyeing, tanning, and in foods for diabetics. Formula: C5H10O5Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014xy?lose (?za? lo?s) n. a colorless pentose sugar, C5H10O5, used in dyeing, tanning, and diabetic foods. [1890?95;