The term ‘sorrel’, originating from the color of flower spikes of sorrel plants, is alternatively used for referring to chestnut (a common coat color in horses). Sorrel horses have a copper-red body, with similar or lighter mane and tail, varying from reddish-gold to chocolate or deep burgundy.
Although many horse enthusiasts believe that sorrel and chestnut are two different colors, there is no difference between the two. It is commonly debated that sorrel denotes coats with lighter shades or clear reddish tint while chestnut describes darker or browner shades.
According to the American Quarter Horse Association, the sorrel represents the copper-red variety of chestnut but can be used for generically referring to chestnut. The term ‘sorrel’ is more commonly used in the Western US, while ‘chestnut’ is typically used in the UK and on the eastern coast of the US.