pen·in·su·la (p?-n?n?sy?-l?, -s?-l?)n. Abbr. Pen. A piece of land that juts out from a larger land mass and is mostly surrounded by water.[Latin paen?nsula : paene, almost + ?nsula, island.]pen·in?su·lar 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.peninsula (p??n?nsj?l?) n (Physical Geography) a narrow strip of land projecting into a sea or lake from the mainland[C16: from Latin, literally: almost an island, from paene pene- + insula island] pen?insular adjUsage: The noun peninsula is sometimes confused with the adjective peninsular: the Iberian peninsula (not peninsular)Peninsula n (Placename) the Peninsula short for the Iberian Peninsula Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014pen?in?su?la (p??n?n s? l?, -?n?ns y? l?) n., pl. -las. 1. land almost completely surrounded by water except for an isthmus connecting it with the mainland. 2. the Peninsula, a. Iberia (def. 1). b. a district in SE Virginia between the York and James rivers: Civil War battles. [1530?40;