rock candyn. A hard confection that is made by cooling a concentrated sugar syrup into large clear crystals, often around a piece of string or a stick.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.rock candy n (Cookery) US and Canadian a hard candy, typically a long brightly-coloured peppermint-flavoured stick, sold esp in holiday resorts. Also called (in Britain and certain other countries): rock Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014rock? can?dy n. sugar in large, hard, cohering crystals. [1715?25] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.