tank

tank — noun

1. a large container, usually made of metal or strong plastic, used for keeping or

1.nounA2
Definition

a large container, usually made of metal or strong plastic, used for keeping or moving liquids or gases such as water, fuel, or chemicals.

Example

The mechanic drained the oil from the tank before replacing the filter.

noun modifier: oil tank / fuel tank

Water tanks on the roof collect rainwater for the garden during the dry season.

Common collocations
  • a tank of
  • fuel tank
  • water tank
  • fish tank
  • gas tank
  • storage tank
  • fill the tank
  • drain the tank
  • tank capacity
  • tank level
Synonyms
  • container

    much more general; any object that holds something

  • reservoir

    a large natural or man-made lake for storing water

  • vat

    a large tub or tank for liquids in industrial settings

  • cistern

    a tank for storing water, especially in a building or underground

Grammar Patterns

a tank of [liquid/gas]

[noun] tank (e.g. fish tank, petrol tank)

Usage Note

Frequently combines with a noun that tells you what the tank contains: petrol tank, fish tank, water tank, gas tank, fuel tank.

Common Mistakes

I filled the car with a container of petrol.
I filled the car with a tank of petrol.
A 'container' is any vessel; a 'tank' is specifically a large, often built-in vessel for liquids or gases.

2. a heavily armoured military fighting vehicle with large guns that runs on contin

2.nounB1
Definition

a heavily armoured military fighting vehicle with large guns that runs on continuous metal belts looped around wheels, allowing it to move across rough ground.

Example

The army sent six tanks to guard the border crossing near the village.

Jiwoo watched a documentary about how tanks changed the way wars were fought in the twentieth century.

historical usage context

Common collocations
  • tank battalion
  • tank commander
  • tank crew
  • tank battle
  • heavy tank
  • light tank
  • drive a tank
  • tank regiment
Synonyms
  • armoured vehicle

    broader category; includes tanks and other protected military vehicles

  • armoured car

    a lighter, wheeled vehicle with armour, not a tank

  • battle tank

    a full-size combat tank, as opposed to lighter armoured vehicles

Grammar Patterns

[number] + tank(s)

tank + [noun] (e.g. tank commander, tank battalion)

Usage Note

Often used attributively before another noun: tank commander, tank battalion, tank battle, tank engine. The plural is irregular only in that military contexts often use 'tank' as an uncountable modifier ('tank division').

3. a situation where a person or organization starts competing directly in another'

3.nounC1
Definition

a situation where a person or organization starts competing directly in another's established area of business or activity, often threatening their position.

Example

The new streaming service is now competing in the tank of the traditional TV networks.

figurative: in the tank of [competitor]

Hassan worried that the large supermarket chain was operating in the tank of his small grocery store.

Common collocations
  • in someone's tank
  • move into someone's tank
  • compete in the tank of
Synonyms
  • turf

    more common idiom ('on someone's turf'); informal, meaning someone's territory or area of control

  • territory

    neutral term for an area of activity or interest

  • domain

    formal; an area of activity or knowledge controlled by someone

Grammar Patterns

in someone's tank

on someone's tank

Usage Note

A figurative and informal use, most common in business and competitive contexts. The phrase 'in someone's tank' suggests territory that someone previously controlled alone.

4. a man-made pool or lake, often built to store water for a town, farm, factory, o

4.nounB1
Definition

a man-made pool or lake, often built to store water for a town, farm, factory, or for swimming.

Example

The village built a large tank to store water for the rice fields during the dry months.

Swimming in the old quarry tank was forbidden after two accidents last summer.

collocation: quarry tank

Common collocations
  • swimming tank
  • water tank
  • ornamental tank
  • quarry tank
  • storage tank
Synonyms
  • reservoir

    larger, often supplies water to a whole city

  • pond

    smaller and often natural, but can be man-made

  • pool

    small body of still water; a swimming pool is man-made

Grammar Patterns

a tank of [water]

storage tank

Usage Note

This sense is more common in British and Australian English than in American English, where 'reservoir' or 'pond' is preferred for artificial bodies of water.

Common Mistakes

The ship sailed across the tank.
The ship sailed across the lake/reservoir.
A 'tank' in this sense is a relatively small man-made pool, not a large navigable body of water.

5. a piece of clothing without sleeves that covers the upper part of the body, typi

5.nounB1
Definition

a piece of clothing without sleeves that covers the upper part of the body, typically worn in warm weather or during exercise.

Example

Christopher wore a white tank top and shorts to the beach on Saturday.

Tank tops are popular in summer because they let your arms move freely and keep you cool.

reason clause

Common collocations
  • wear a tank top
  • cotton tank top
  • white tank top
  • tank top and shorts
Synonyms
  • singlet

    British and Australian term for a sleeveless top

  • vest

    British English term for an undergarment or sleeveless top

Grammar Patterns

wear a tank top

a tank top

Usage Note

Called a 'singlet' or 'vest' in British English. The name comes from the early 20th-century 'tank suit' — a one-piece bathing suit worn in swimming tanks (artificial pools).

Common Mistakes

She wore a tank to the party.' (ambiguous)
She wore a tank top to the party.
In casual American English 'a tank' can mean a tank top, but it's clearer to say 'tank top' to avoid confusion with the vehicle.

6. the quantity of liquid, gas, or other material that a tank holds when it is full

6.nounB1
Definition

the quantity of liquid, gas, or other material that a tank holds when it is full.

Example

The car can drive about five hundred kilometres on a full tank of petrol.

collocation: a full tank of

Nikhil used an entire tank of paint to cover the walls of the living room.

Common collocations
  • a full tank
  • half a tank
  • a tank of gas
  • a tank of petrol
  • a tank of water
  • a tank of paint
Synonyms
  • tankful

    the same meaning, less common spelling variant

  • load

    a more general term for the amount carried by a vehicle

Grammar Patterns

a tank of [substance]

a full tank

half a tank

Usage Note

Often follows 'full' or 'half' — 'a full tank,' 'half a tank.' 'A tank of gas/petrol' is extremely common in driving contexts.

Common Mistakes

I have a container of gas left.
I have half a tank of gas left.
Use 'tank' when referring to the fuel capacity of a vehicle.

tank — verb

Word family

  • tanker
    nounB1
  • tanking
    nounC1
  • tankard
    nounC1
  • tank top
    nounB1

Synonym discussion

Sense: verb/1

All four words describe a decrease, but they differ in speed, severity, and formality. 'Tank' (informal) suggests a fast, dramatic fall — often in finance or business contexts — and can also be used metaphorically ('confidence tanked'). 'Plummet' is similar in speed but slightly more formal, often used in journalism ('prices plummeted'). 'Crash' implies a sudden and complete collapse, carrying the strongest sense of disaster ('the stock market crashed'). 'Slump' is slower and less dramatic — a gradual decline over a period of time ('sales slumped during the recession'). 'Tumble' is softer than tank or crash, suggesting a noticeable but not catastrophic drop ('the company's shares tumbled 5%'). Example: 'The stock price tanked after the CEO resigned' (fast, dramatic, informal) vs 'The stock price slumped over several months' (gradual, formal).

Common collocations

Phrases

  • a tank of
  • a full tank
  • half a tank
  • in the tank
  • tank top

Prepositions

  • of (a tank of water)
  • in (in the tank)
  • from (from the tank)
  • with (tank with sealant)
  • into (move into someone's tank)

Etymology

GujaratiSanskritEnglish

The word 'tank' entered English in the early 1600s from Gujarati 'tānkh' (a reservoir or cistern), which trace back to Sanskrit 'tadāga' (a pond or lake). The original English meaning was 'an artificial pool or reservoir for water.' During World War I (1915-1916), the British Army needed a code name for a secret new armoured fighting vehicle. Workers building the vehicles were told they were making 'water tanks' for the army in Mesopotamia, and the name stuck. The verb meanings (to decline rapidly, to lose intentionally) emerged in American English in the early 20th century, possibly from the image of a tank sinking or being knocked out of action.