post·card also post card (p?st?kärd?)n.1. A printed card with space on one side for an address and a postage stamp, used for sending a short message through the mail.2. See postal card.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.postcard (?p??st?k??d) na card, often bearing a photograph, picture, etc, on one side, (picture postcard), for sending a message by post without an envelope. Also called (US): postal card Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014post?card` or post? card`, n. 1. a small, commercially printed card usu. having a picture on one side and space for a postage stamp, address, and message on the other. 2. postal card (def. 1). [1865?70] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.