A stallion is an adult male horse that can father baby horses, called foals. While people use the word “horse” for both males and females, stallion specifically means a male. Female horses are called mares, and young horses are called colts (males) or fillies (females).

Stallions are typically stronger and more muscular than mares, and they often have a bold, spirited personality. Throughout history, stallions have been prized for breeding programs because their traits pass down to their offspring. A rancher hoping to produce fast racehorses or strong workhorses would carefully choose which stallion to breed with their mares.

Because of their powerful build and energetic nature, stallions require experienced handlers. A male horse that has been trained to be calmer and gentler is called a gelding, and most horses people ride are either mares or geldings rather than stallions.

Today, people sometimes use stallion figuratively to describe someone strong, impressive, or commanding, though this usage is informal and often playful.