clas·si·fi·ca·tion (kl?s??-f?-k??sh?n)n.1. The act, process, or result of classifying.2. A category or class.3. Biology The systematic grouping of organisms into categories on the basis of evolutionary or structural relationships between them; taxonomy.clas?si·fi·ca·to?ri·ly (kl?s??-f?-k?-tôr??-l?, kl?-s?f??-) adv.clas?si·fi·ca·to?ry (kl?s??-f?-k?-tôr??, kl?-s?f??-, kl?s??-f?-k??t?-r?) 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.classification (?klæs?f??ke???n) n1. systematic placement in categories2. one of the divisions in a system of classifying3. (Biology) biology a. the placing of animals and plants in a series of increasingly specialized groups because of similarities in structure, origin, molecular composition, etc, that indicate a common relationship. The major groups are domain or superkingdom, kingdom, phylum (in animals) or division (in plants), class, order, family, genus, and speciesb. the study of the principles and practice of this process; taxonomy4. (Government, Politics & Diplomacy) government the designation of an item of information as being secret and not available to people outside a restricted group[C18: from French; see class, -ify, -ation] ?classifi?cational adj ?classifi?catory adjCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014clas?si?fi?ca?tion (?klæs ? f??ke? ??n) n. 1. the act of classifying. 2. the result of classifying or being classified. 3. one of the classes into which things are classified. 4. the assignment of organisms to groups within a system of categories distinguished by structure, origin, etc. [1780?90;