A pony is a small horse that remains short throughout its life, typically standing less than 14.2 hands tall (about 4 feet 9 inches at the shoulder). A hand is an old unit of measurement equal to four inches, based on the width of a human hand. Unlike a foal, which is a young horse that will grow larger, ponies are fully grown animals that naturally stay small.

Ponies have distinctive physical characteristics that set them apart from horses. They tend to have stockier bodies, thicker manes and tails, shorter legs, and broader barrels. Many pony breeds, like Shetland ponies or Welsh ponies, originally lived in harsh climates where their smaller size and sturdy build helped them survive cold winters and rocky terrain. Their compact bodies needed less food than full-sized horses, which made them valuable for families that couldn't afford to feed a large horse.

Because of their smaller size and often gentler temperaments, ponies frequently serve as first mounts for children learning to ride. However, ponies can be surprisingly strong for their size and sometimes develop stubborn streaks, so experienced riders know not to underestimate them.

The word pony also appears in a few other contexts: in older slang, a pony could mean a guide that helped students with language assignments, though this usage is becoming less common. And when someone says “pony up,” they mean to pay money owed or contribute your share.