Corn: A small callused area of skin caused by local pressure that irritates tissue over a bony prominence. Although the surface area of a corn may be small, the area of hardening actually extends into the deeper layers of skin and flesh. The inside projection of the corn is what causes discomfort. Corns most commonly occur over a toe, where they form what is referred to as hard corns. Between the toes, pressure can form a soft corn of macerated skin, which often yellows. Corns can be softened by soaking them in hot water, with or without softening agents that are available over the counter or by prescription. In some cases, minor outpatient surgery may be used to remove excess corn tissue. A corn on the toe is also called a clavus.