horse of a different color, a

horse of a different color

Something completely different or separate, especially in comparison to something else. I've always found math to be easy, but calculus is a horse of a different color.
See also: color, different, horse, of
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

horse of a different color, a

Also, a horse of another color. Another matter entirely, something else. For example, I thought that was her boyfriend but it turned out to be her brother-that's a horse of a different color . This term probably derives from a phrase coined by Shakespeare, who wrote "a horse of that color" ( Twelfth Night, 2:3), meaning "the same matter" rather than a different one. By the mid-1800s the term was used to point out difference rather than likeness.
See also: different, horse, of
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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