pigmented mole see under nevus. mole 1 (mōl) n. A skin lesion, commonly a nevus, that is typically raised and discolored. mole 2 (mōl) n. A fleshy abnormal mass formed in the uterus by the degeneration or abortive development of an ovum. mole 1. Etymology: L, mass, Usage notes: informal. 1 a pigmented nevus. 2 (in obstetrics) a hydatid mole. mole 2