What do you call a well balanced horse?

The joke “What do you call a well-balanced horse? Stable” is a play on words involving the double meaning of “stable.” In one sense, a “stable” is a building where horses are kept, which relates directly to the horse in the joke. In another sense, “stable” is an adjective that describes something that is steady, balanced, and not likely to give way or overturn, which can metaphorically apply to someone’s mental state or situation. By asking what you call a “well-balanced” horse, the setup implies looking for a descriptor of its demeanor, but the punchline humorously twists it to mean the actual place where a horse is housed.