A bronco is a wild or partially tamed horse, especially the kind found in the western United States and Mexico. These horses are known for being spirited and difficult to ride. When a cowboy tries to ride an untamed bronco, the horse will often buck violently, twisting and kicking its hind legs high in the air to try to throw the rider off its back.

In the American West during the 1800s and early 1900s, cowboys had to break in wild broncos to make them useful for ranch work. This was dangerous, skilled work that required courage, balance, and patience.

Today, bronco riding is a popular rodeo sport where riders try to stay on a bucking horse for eight seconds while holding on with just one hand. The horses used in rodeos are called broncos even though they're specially trained for the sport, not truly wild.

You might also hear someone describe a person as acting like a bronco when they're being stubborn or hard to control, though this usage is less common. The Denver Broncos football team took their name from these tough, spirited horses.