Colt (horse)

A colt is a young male horse,^[1] under the age of four. Older male horses are called either a "stallion", if left fertile, or a "gelding" if neutered. The verb "to geld" refers to the process of neutering a stallion.

A young female horse is called a filly^[1] until age four, and a mare thereafter.

A group of colts is called a "rag".