Final answer:
A nail is considered an appendage of the skin, serving as an accessory structure of the integumentary system to protect the tips of fingers and toes and aid in various functions.
Step-by-step explanation:
The term that is considered an appendage of the skin is a nail. Nails are accessory structures of the integumentary system, which includes the skin, hair, nails, sweat glands, and sebaceous glands. Nails are similar to claws in other animals and are primarily made up of dead keratinized cells. These structures protect the extremities of our fingers and toes, and their primary function includes protecting the distal phalanx, the fingertip, and the surrounding soft tissues from injuries. Nails grow from the nail bed, adding cells at the base and pushing older cells forward; hence they grow longer.