con·fec·tion·ers' sugar
(kən-fĕk′shə-nərz)n. Finely pulverized sugar, usually with cornstarch added. Also called powdered sugar.
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.
confectioners' sugar
or confectionery sugar
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
confec′tioners' sug′ar
n. an extra-fine variety of powdered sugar.
Symbol: XXXX [1890–95]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.