quaa·lude (kw??lo?od?)n. A capsule or tablet of the illicit drug methaqualone.[Originally a trademark.]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.Quaalude (?kwe?lu?d) n (Pharmacology) US a proprietary name for methaqualoneCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014Quaa?lude (?kwe? lud) Trademark. a brand of methaqualone. Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.