Colt- A young male horse

Filly- A young female horse

Foal- A horse less than one year old

Gelding- A neutered male horse

Halter- A type of equipment that goes over the horses head, and is used with a lead rope  to lead (move) the horse.

Horse- A species of mammal more specifically a type of  odd-toed ungulate (equine). Ungulate means hoofed animal, and horses have one hoof on each leg. This is contrasted with deer, which are even-toed ungulates, because deer have legs with two toes or hooves.

Mare- A female horse

Stallion- An intact male horse