a saddle horse trained to separate calves, steers, etc., from a herd.
Origin of cutting horse
First recorded in 1880–85
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for cutting horse
US and Canadian a saddle horse trained for use in separating an individual animal, such as a cow, from a herd
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012