Toenails are made of a tough protein called keratin and have many different parts:

eponychium or cuticle, is the fold of skin at the proximal end of the nail.
paronychium is the fold of skin on the sides of the nail.
hyponychium is the attachment between the skin of the toe and the distal end of the nail.
nail plate is the hard and translucent portion, composed of keratin.
nail bed is the adherent connective tissue that underlies the nail, often referred to as the “quick.”
lunula is the crescent shaped whitish area of the nail bed (when visible)
nail fold is a fold of hard skin overlapping the base and sides of a toenail.