What is the name of the fold of skin that overlaps the side of the nail?

The term that designates the fold of skin overlapping the side of the nail is the lateral nail fold. This structure serves a protective function by creating a barrier between the nail plate and the surrounding skin, which helps to prevent infections and injuries to the nail matrix beneath. The lateral nail fold also plays a role in maintaining nail health, as it aids in the adherence of the nail plate to the underlying tissues.

Other terms in the options refer to different parts of the nail anatomy. The nail plate is the hard, protective part of the nail that we can see, while the lunula is the pale, crescent-shaped area at the base of the nail plate. Nail grooves are the indentations that exist between the nail plate and the surrounding skin. Each of these components contributes to the overall structure and function of the nail but does not describe the fold of skin specifically overlapping the side of the nail.