mole

mole — noun

1. a small furry animal with weak eyesight that lives almost entirely underground,

1.nounB1
Definition

a small furry animal with weak eyesight that lives almost entirely underground, digging tunnels and feeding on insects and worms

Example

Zayd's garden had several mole tunnels running just beneath the soil surface.

collocation: mole tunnels

The mole's dark fur helps it slide through narrow tunnels without getting dirty.

possessive: mole's dark fur

Common collocations
  • mole tunnel
  • mole hill
  • mole run
  • blind as a mole
Synonyms
  • shrew

    a similar small burrowing mammal, but shrews are smaller and have visible eyes

Usage Note

The plural form is moles. The piles of earth pushed up by moles at tunnel openings are called molehills.

Common Mistakes

A mole is a type of rat that lives under the ground.
A mole is a small mammal that digs tunnels underground.
Moles are not rodents; they belong to the order Eulipotyphla, which includes shrews and hedgehogs.

2. a small, usually dark area of pigmentation on the surface of human skin that can

2.nounB1
Definition

a small, usually dark area of pigmentation on the surface of human skin that can be flat or slightly raised and is typically not harmful

Example

Jenna noticed a new mole on her forearm and asked the doctor to examine it.

verb pattern: noticed a mole + asked doctor to examine

Most moles are harmless, but you should watch for changes in their shape or colour.

advice pattern: most moles are harmless, but you should watch

Common collocations
  • raised mole
  • flat mole
  • dark mole
  • check a mole
  • mole removal
Synonyms
  • freckle

    a smaller, lighter spot that appears after sun exposure and may fade in winter

  • birthmark

    a coloured mark on the skin that is present from birth

Usage Note

Used especially of brown or black spots. The medical term is melanocytic nevus. Always consult a doctor if a mole changes shape, colour, or size.

Common Mistakes

He has a mole on his face that is red and itchy, which is normal.
He has a mole on his face that is red and itchy, so he should see a doctor.
An itchy or red mole may indicate a problem and should be checked by a medical professional.

3. a person who secretly works inside an organisation or government and passes conf

3.nounB2
Definition

a person who secretly works inside an organisation or government and passes confidential information to a rival group or enemy

Example

The company discovered a mole who had been selling customer data to a competitor.

relative clause: mole who had been selling

Security forces arrested a mole inside the ministry who leaked classified documents.

Common collocations
  • plant a mole
  • expose a mole
  • uncover a mole
  • mole inside
  • corporate mole
Synonyms
  • spy

    a broader term for anyone who secretly collects information; a mole is a specific type of spy who has infiltrated an organisation

  • double agent

    a spy who works for two opposing sides at the same time

  • infiltrator

    someone who enters a group to gain information; less specific than mole

Usage Note

Common in espionage and corporate contexts. Unlike a regular spy, a mole is embedded within the target organisation, often for a long time, before beginning intelligence activities.

4. a standard unit in chemistry for describing how much of a chemical is present, d

4.nounC1
Definition

a standard unit in chemistry for describing how much of a chemical is present, determined by counting the atoms or molecules it contains

Example

In chemistry class, Joon learned to calculate the moles in a sample of sodium chloride.

classroom context: calculate the number of moles

One mole of any substance contains roughly six hundred and two sextillion particles.

definitional: one mole contains [Avogadro's number] particles

Common collocations
  • mole of
  • number of moles
  • mole ratio
  • mole concept
  • per mole

Grammar Patterns

mole of + noun

Usage Note

Abbreviated as 'mol' in scientific writing. One mole equals approximately 6.022 × 10²³ particles (Avogadro's number). The term is almost exclusively used in chemistry and physics contexts.

Common Mistakes

A mole is a unit for measuring weight.
A mole is a unit for measuring the amount of a substance based on the number of particles.
The mole does not measure weight; it measures the quantity of particles.

5. a large stone or concrete barrier built out from the coast into the sea, designe

5.nounC1
Definition

a large stone or concrete barrier built out from the coast into the sea, designed to protect the shore from waves and to create a sheltered harbour

Example

The fishing boats were safe behind the old stone mole that blocked the strong waves.

protective function: safe behind the mole

Engineers designed a new concrete mole to prevent the harbour from silting up.

Common collocations
  • stone mole
  • concrete mole
  • mole harbour
  • build a mole
  • mole extending into the sea
Synonyms
  • breakwater

    a more common term for a structure that protects a shore from waves

  • jetty

    a smaller structure that projects into water, often used for loading and unloading boats

  • pier

    a structure built out over water for people to walk on or for ships to dock

Usage Note

Less common in everyday conversation; the words 'breakwater' or 'jetty' are more widely used in modern English. 'Mole' in this sense is found more often in historical or technical descriptions of harbour structures.

6. a thick, rich Mexican sauce made from dried chilli peppers and often including c

6.nounB2
Definition

a thick, rich Mexican sauce made from dried chilli peppers and often including chocolate, nuts, and spices, typically served with meat or poultry

Example

Mole sauce takes hours to prepare, but the complex flavour is worth the effort.

preparation: takes hours to prepare

Sofie ordered chicken with mole and rice at the new Mexican restaurant.

ordering food: chicken with mole

Common collocations
  • chicken mole
  • mole sauce
  • mole poblano
  • mole negro
  • prepare mole

Usage Note

Pronounced /ˈmoʊ.leɪ/ (moh-LAY), not like the animal. The word comes from Nahuatl 'mōlli', meaning sauce. Many varieties exist, including mole poblano (from Puebla) and mole negro (from Oaxaca).

Common Mistakes

Mole is a Mexican sauce that is always very spicy.
Mole is a Mexican sauce that can range from mild to spicy, and it is known for its rich, layered flavour.
Not all mole is extremely hot; some varieties emphasise depth of flavour over heat.
Idioms

make a mountain out of a molehill

idiom

to treat a small problem as if it were very serious

Femi spilled a little milk and started crying, making a mountain out of a molehill.

The manager is making a mountain out of a molehill over a tiny mistake in the report.

Word family

Synonym discussion

Sense: noun/2

A mole (痣) is a small, usually dark spot on the skin that may be flat or raised and is typically present from childhood or appears later in life. A freckle (雀斑) is a smaller, lighter brown spot that appears after sun exposure and often fades in winter, whereas a mole remains dark all year. A birthmark (胎記) is a coloured mark ranging from pink to deep brown that is present from birth and can cover a much larger area. While a single mole is usually harmless, multiple moles or a mole that changes shape warrants medical attention; freckles and most birthmarks are benign. For example: 'Ryo's dermatologist said his new mole looked fine,' but 'Camila's freckles come out every summer,' and 'Jenna has a small pink birthmark on her wrist.'

mole ↗freckle ↗birthmark ↗

Common collocations

Nouns

  • mole tunnel
  • mole hill
  • mole removal
  • mole sauce
  • mole poblano

Phrases

Prepositions

  • mole on the skin
  • mole inside an organisation
  • mole of a substance
  • mole in the sea

Etymology

Nahuatl (sauce)Latin (breakwater)Old English (skin mark)Middle English (animal)German (chemistry unit)

The word 'mole' has multiple origins that converged in English. The animal sense comes from Middle English 'molle', related to Middle Low German 'mol'. The skin-mark sense comes from Old English 'māl' meaning a spot or stain, related to Old High German 'meil'. The breakwater sense comes from Latin 'moles' meaning a large mass or barrier. The chemistry unit was introduced in German as 'Mol' in 1900, short for 'Molekül' (molecule). The sauce sense comes from Nahuatl 'mōlli', meaning sauce or stew, adopted into Spanish and then English.