Is a Shank part of horse?

Yes, a shank is a part of a horse! It refers to the lower part of the horse's leg, specifically:

* The lower part of the hind leg: This is the area between the hock joint and the fetlock joint.

* The part of the bridle that connects the bit to the headstall: This is also called a "cheek piece" or "rein stop."

So, depending on the context, "shank" can refer to either a part of the horse's leg or a part of the bridle.