Nevus is the medical term for a mole.
They vary in size and shape and can cover an area of the body. Nevi are often seen in 'bathing trunk', 'cape', 'shirt', and various facial or scalp distributions. Unlike some birthmarks, nevi will not disappear as the child grows older. The cause of giant nevi is unknown. Aside form the cosmetic issues, people with giant nevi have an increased risk of developing skin cancer.