mole

1 of 6

noun (1)

ˈmōl 

: a pigmented spot, mark, or small permanent protuberance on the human body

especially : nevus

mole

2 of 6

noun (2)

1

: any of numerous burrowing insectivores (especially family Talpidae) with tiny eyes, concealed ears, and soft fur

2

: one who works in the dark

3

: a machine for tunneling

4

: a spy (such as a double agent) who establishes a cover long before beginning espionage

broadly : one within an organization who passes on information

mole

3 of 6

noun (3)

: an abnormal mass in the uterus especially when containing fetal tissues

mole

4 of 6

noun (4)

1

: a massive work formed of masonry and large stones or earth laid in the sea as a pier or breakwater

2

: the harbor formed by a mole

mole

5 of 6

noun (5)

ˈmōl 

variants or less commonly mol

plural moles

: the base unit of amount of pure substance in the International System of Units that is defined as having exactly 6.02214076 x 10²³ indivisible units (such as atoms or molecules) of that substance

First you would need to measure out one mole of salt. Remember that one mole of a compound equals its relative molecular mass in grams, so to obtain one mole of sodium chloride you would weigh out 58.5 g …

—John Atkinson and Carol Hibbert

one mole of helium contains 4 grams

mole

6 of 6

noun (6)

mo·​le ˈmō-lā 

: a spicy sauce made with chiles and usually chocolate and served with meat

Synonyms

Noun (2)

• agent
• asset
• emissary
• intelligencer
• operative
• spook
• spy
• undercover

Examples of mole in a Sentence

Noun (2)

for years we have had a mole in the enemy's national intelligence agency

Recent Examples on the Web

Noun

Phelps is eventually revealed to be the IMF mole and dies while trying to flee (for good, this time). —EW.com, 24 May 2025

But in November 2024, a nurse friend shared her concerns about the mole, prompting the 46-year-old mom of one to see her doctor about the mark on her skin. —Cara Lynn Shultz, People.com, 12 May 2025

This episode sees Helberg back in action when Beatrix Hasp (Rhea Perlman) tries to find who in her crew is a mole — with the unexpected help of Charlie. —Matt Minton, Variety, 10 May 2025

More on Moles Voles Vole damage is often confused for mole damage. —Arricca Elin Sansone, Southern Living, 8 May 2025

Word History

Etymology

Noun (1)

Middle English, from Old English māl; akin to Old High German meil spot

Noun (2)

Middle English; akin to Middle Low German mol

Noun (3)

Middle English, from Latin mola mole, literally, mill, millstone — more at mill

Noun (4)

Middle French, from Old Italian molo, from Late Greek mōlos, from Latin moles, literally, mass, exertion; akin to Greek mōlos exertion

Noun (5)

German Mol, short for Molekulargewicht molecular weight, from molekular molecular + Gewicht weight

Noun (6)

Mexican Spanish, from Nahuatl mōlli sauce

First Known Use

Noun (1)

14th century, in the meaning defined above

Noun (2)

14th century, in the meaning defined at sense 1

Noun (3)

15th century, in the meaning defined above

Noun (4)

circa 1548, in the meaning defined at sense 1

Noun (5)

1902, in the meaning defined above

Noun (6)

1882, in the meaning defined above

Phrases Containing mole

• mole cricket
• mole rat
• naked mole rat
• star-nosed mole

Rhymes for mole

• boal
• bole
• bowl
• coal
• droll
• foal
• goal
• hole
• knoll
• kol
• noll
• nolle

Kids Definition

mole

1 of 3 noun

ˈmōl 

: a small usually brown and sometimes slightly raised permanent spot on the skin

mole

2 of 3 noun

: any of numerous burrowing mammals with tiny eyes, concealed ears, and soft fur that eat insects

mole

3 of 3 noun

: a pier made of heavy solid material (as concrete or stone) that protects a harbor from rough seas

Etymology

Noun

Old English māl "spot on the skin"

Noun

Middle English mole "burrowing animal"

Noun

from early French mole "stone pier," from early Italian molo (same meaning), derived from Latin moles, literally "a mass"

Medical Definition

mole

1 of 3 noun

ˈmōl 

: a pigmented spot, mark, or small permanent protuberance on the human body

especially : nevus

mole

2 of 3 noun

: an abnormal mass in the uterus:

a

: a blood clot containing a degenerated fetus and its membranes

b

: hydatidiform mole

mole

3 of 3 noun

variants also mol

ˈmōl 

: the base unit in the International System of Units for the amount of pure substance that contains the same number of elementary entities as there are atoms in exactly 12 grams of the isotope carbon 12

a mole of photons

a mole of sodium chloride