re·con·nais·sance also re·con·nois·sance (r?-k?n??-s?ns, -z?ns)n. An inspection or exploration of an area, especially one made to gather military information.[French, from Old French reconoissance, recognition, from reconoistre, reconoiss-, to recognize; see recognize.]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.reconnaissance (r??k?n?s?ns) or reconnoissancen1. (Military) the act of reconnoitring2. (Military) the process of obtaining information about the position, activities, resources, etc, of an enemy or potential enemy3. (Civil Engineering) a preliminary inspection of an area of land before an engineering survey is made[C18: from French, from Old French reconoistre to explore, recognize]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014re?con?nais?sance or re?con?nois?sance (r??k?n ? s?ns, -z?ns) n. 1. the act of reconnoitering. 2. a general examination or survey of a region, usu. followed by a detailed survey. [1800?10;