what·cha·ma·call·it (w?ch??-m?-kôl??t, w?ch?-, hw?ch?-, hw?ch?-)n. Something whose name is unknown or forgotten.[Alteration of what you may call it.]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.whatchamacallit (?w?t??m??k??l?t) n another word for whatsitCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014