mole¹ / mōl/ • n. 1. a small burrowing insectivorous mammal (family Talpidae) with dark velvety fur, a long muzzle, and very small eyes. Its several species include the eastern mole (Scalopus aquaticus) of North America. 2. a spy who achieves over a long period an important position within the security defenses of a country. ∎  someone within an organization who anonymously betrays confidential information.mole² / mōl/ • n. a small, often slightly raised blemish on the skin made dark by a high concentration of melanin.mole³ / mōl/ • n. a large solid structure on a shore serving as a pier, breakwater, or causeway. ∎  a harbor formed or protected by such a structure.mole⁴ / mōl/ • n. Chem. the SI unit of amount of substance, equal to the quantity containing as many elementary units as there are atoms in 0.012 kg of carbon-12.mole⁵ / mōl/ • n. Med. an abnormal mass of tissue in the uterus. See also hydatidiform mole.

mole Any of several species of small, burrowing, mainly insectivorous mammals that live in various habitats worldwide. The European mole, Talpa europaea, has short brown or black fur, a short tail, and wide clawed forefeet for digging tunnels. Its eyes are sensitive only to bright light. Length: to 18cm (7in). Family Talpidae.

mole2 small burrowing mammal. XIV. ME. mol(l)e, mulle, prob. — MDu. mol, moll(e), (M)LG. mol, mul.

mole See TALPIDAE.