A mole or melanocytic nevus was a type of lesion that contained nevus cells.
One of Roberta Lincoln's birthmarks took the form of a small mole on her left shoulder. (TOS: "Assignment: Earth")
Seska had a little mole on her stomach. In 2372, Chakotay goaded Maje Cullah by expressing his fondness for it. (VOY: "Maneuvers")