sidecheck (?sa?d?t??k) n (Horse Training, Riding & Manège) part of a horse’s harnessCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014side?check (?sa?d?t??k) n. a checkrein passing from the bit to the saddle of the harness. [1890?95, Amer.] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.