mole

UK: /ˈməʊl/

US: /moʊl/

US: (mōl for 1-5; mō′lā; Sp. mô′le for 6)

WordReference Random House Learner's Dictionary of American English © 2026

mole¹ /moʊl/   n. [countable]

1. Mammals a small, insect-eating mammal living chiefly underground.
2. Government a spy who becomes part of and works from within the ranks of an enemy intelligence agency.

mole² /moʊl/   n. [countable]

1. Pathology, Anatomy a small spot or blemish on the human skin, present from birth, usually of a dark color:
   a small mole on her cheek.

WordReference Random House Unabridged Dictionary of American English © 2026

mole¹  (mōl), n. 

1. Mammals any of various small insectivorous mammals, esp. of the family Talpidae, living chiefly underground, and having velvety fur, very small eyes, and strong forefeet.
2. Government a spy who becomes part of and works from within the ranks of an enemy governmental staff or intelligence agency. Cf. double agent. 
3. Mechanical Engineering [Mach.] a large, powerful machine for boring through earth or rock, used in the construction of tunnels.

• 1350–1400; Middle English molle; akin to Middle Dutch, Middle Low German mol

mole²  (mōl), n. 

1. Pathology, Anatomy a small, congenital spot or blemish on the human skin, usually of a dark color, slightly elevated, and sometimes hairy;
   nevus.

• bef. 1000; Middle English; Old English māl; cognate with Old High German meil spot, Gothic mail wrinkle

mole³  (mōl), n. 

1. Civil Engineering a massive structure, esp. of stone, set up in the water, as for a breakwater or a pier.
2. Civil Engineering an anchorage or harbor protected by such a structure.

• Latin mōlēs mass, dam, mole
• 1540–50

mole⁴  (mōl), n. [Chem.]

1. Chemistry the molecular weight of a substance expressed in grams;
   gram molecule.

Also, mol. 

• German Mol, short for Molekül molecule
• 1900–05

mole⁵  (mōl), n. [Pathol.]

1. Pathology a fleshy mass in the uterus formed by a hemorrhagic dead ovum.

• Neo-Latin mola, special use of mola millstone
• 1605–15

mo•le⁶  (mō′lā; Sp. mô′le), n. [Mexican Cookery.]

1. Food a spicy sauce flavored with chocolate, usually served with turkey or chicken.

• Nahuatl mōlli sauce; compare guacamole
• Mexican Spanish
• 1925–30

Collins Concise English Dictionary © HarperCollins Publishers::

mole / məʊl/ noun

1. any small burrowing mammal, of the family Talpidae, of Europe, Asia, and North and Central America: order Insectivora (insectivores). They have velvety, typically dark fur and forearms specialized for digging
2. golden mole ⇒ any small African burrowing molelike mammal of the family Chrysochloridae, having copper-coloured fur: order Insectivora (insectivores)
3. a spy who has infiltrated an organization and, often over a long period, become a trusted member of it

Etymology: 14th Century: from Middle Dutch mol, of Germanic origin; compare Middle Low German mol

mole / məʊl/ noun

1. a breakwater
2. a harbour protected by a breakwater

Etymology: 16th Century: from French môle, from Latin mōlēs mass

mole / məʊl/ noun

1. a nontechnical name for naevus

Etymology: Old English māl; related to Old High German meil spot

mole / məʊl/ noun

1. the basic SI unit of amount of substance; the amount that contains as many elementary entities as there are atoms in 0.012 kilogram of carbon-12. The entity must be specified and may be an atom, a molecule, an ion, a radical, an electron, a photon, etc

Etymology: 20th Century: from German Mol, short for Molekül molecule