Here's a breakdown of terms:
* Stallion: An adult male horse that has not been castrated. They are known for their strength, size, and often, a more aggressive temperament than geldings.
* Gelding: A male horse that has been castrated. They are generally calmer and less aggressive than stallions.
* Mare: A female horse.
* Foal: A young horse of either sex (usually under a year old).
* Colt: A young male horse (usually under four years old).
* Filly: A young female horse (usually under four years old).
Let me know if you have any other questions about horse terminology!