The term for a young horse is "foal." A foal is typically defined as a horse that is less than one year old. Foals are often born in the spring and are known for their rapid growth and playful behavior. Foals usually stay with their mothers for several months, during which they nurse and gradually start to eat solid food. They begin to gain independence, exploring their environment and interacting with other horses. As they mature, foals go through various developmental stages, eventually becoming yearlings and then adult horses as they approach their second birthday.