Integument is a noun that refers to a tough, outer protective layer.

Our word of the day comes almost directly from the Latin word integumentum (in teg you MEN toom) which means ‘covering, shield or wrapping.’ The word is often used in reference to an animal’s outer shell or protective skin, but here’s an example that can be used in reference to humans:

When it gets this cold outside, I wish I had some kind of an integument to protect me from the single digit weather. Of course, this added layer of skin wouldn’t be such a good thing in the summer.