rock gardenn.1. A rocky area in which plants particularly adapted to such terrain are cultivated.2. A garden in which rocks are arranged and plants cultivated in a carefully designed, decorative scheme. Also called rockery.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 garden n (Horticulture) a garden featuring rocks or rockeries Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014rock? gar`den n. a garden on rocky ground or among rocks, for the growing of alpine or other plants. Also called rockery. [1830?40] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.