Why Is a Horse Called a Stud?

The word "stud" comes from the Old English stod meaning "herd of horses, place where horses are kept for breeding". ... Male animals made available for breeding to outside female animals are said to be "standing at stud", or at "stud service", referencing the relatively high probability that they are kept at a stud farm

What's the difference between a stallion and a stud?

form and function

…male horse is called a stallion, the female a mare. A stallion used for breeding is known as a stud. A castrated stallion is commonly called a gelding.

Do stud horses fight?

Although it's the nature of domestic stallions to fight over a harem of mares and their foals, they're not territorial-that is, they don't fight over a piece of real estate. Many stallions kept in the same pasture or pen get along as well as any geldings might, as long as there are no mares to fight over.