* Chestnut: This is the most likely interpretation of "red" for a horse. Chestnuts have a solid, rich red-brown coat, often with a slightly reddish-brown mane and tail. They come in a range of shades from light to dark.
* Bay: Bay horses also have a red-brown body coat, but they have black points (mane, tail, and lower legs).
* Sorrel: This term is sometimes used interchangeably with chestnut, but it often implies a lighter shade of red-brown.
* Liver chestnut: A liver chestnut has a deeper, more reddish-brown coat with a less reddish tinge than a regular chestnut.
* Roan: Roan horses have a base coat (which could be red) mixed with white hairs, giving them a speckled appearance. So you could have a red roan.
Important Note: While a "red" horse likely refers to a chestnut, it's best to be specific when discussing horse colors.
Let me know if you'd like to learn more about any of these horse colors!