The free edge is the part of the nail plate that extends beyond the fingertip and is no longer attached to the nail bed, which is the part you file, shape and cap with polish.
Also known as: nail tip, distal edge, nail edge, free margin
The free edge is the white or translucent part of the nail that grows past the end of the finger. Behind it the nail plate is attached to the nail bed. At the free edge it is not, which is why it looks lighter. The seal under the free edge, where nail meets skin, is the hyponychium (Medscape).
Fingernails grow about 3 to 4 mm a month, so the free edge lengthens by roughly that amount if it is not filed. Growth is faster on longer fingers, in summer and under the age of 30 (Medscape). The shape of the free edge, round, oval, square, squoval, almond or coffin, is what a nail shape describes.
The free edge is where most manicure wear begins. It takes impact and water, and the polish film at the edge lifts first. Capping the free edge, drawing the brush over the tip with each coat, seals it. Round and squoval free edges have no corners to catch and break least. Almond, coffin and stiletto shapes break most (Mavala).
Filing the free edge in one direction, with a fine file, leaves fewer micro-splits than sawing back and forth. Peeling in thin sheets at the free edge is a sign of onychoschizia, usually from repeated wetting and drying.