Nevus is a term for a benign growth on the skin made up of a cluster of cells termed melanocytes that are responsible for the darker color of the cells, which also may be raised higher than the surrounding skin cells. Many doctors consider a nevus the same thing as a mole; birthmarks are included as a type of nevus.
In most people, a nevus or mole may often appear in several places, most commonly in sun-exposed skin. These skin changes are usually benign and thus are non-cancerous; however, rarely one may develop into a skin cancer. The mole or nevus that grows bigger or changes shape and/or color needs evaluation by a dermatologist, who will likely remove the growth.