Term: Natural Weapon
A weapon that a creature is usually born with, and/or obtains and hones over the course of their life. This could the claws of a Catfolk, the jaws of a Gnoll or Kobold, or the spit and breath of a Dragonborn.
All Natural Weapons are considered Unarmed Weapons and share many of the same benefits as such, and all creatures the Natural Weapon is attached are "Trained in" in them.