carbon

IPA/ˈkɑːbən/
KK[kˈɑrbən]IPA/ˈkɑːrbən/

carbon — noun

  • carbonsingular
  • carbonsplural

1. a naturally occurring chemical element, symbol C, that is present in every livin

1.nounB2
Definition

a naturally occurring chemical element, symbol C, that is present in every living thing on the planet and takes different forms including diamond, graphite, coal, and petroleum

Example

Diamonds are made entirely of carbon that has been under extreme heat and pressure for millions of years.

passive: is/are made of carbon

All living organisms on Earth contain carbon, which is why it is called the building block of life.

collocation: contain carbon / building block of life

Common collocations
  • pure carbon
  • contain carbon
  • carbon-based

2. a gas written as CO₂ that is released when fuel is burned or living things breat

2.nounB1
Definition

a gas written as CO₂ that is released when fuel is burned or living things breathe out, and is the main cause of global warming

Example

Many countries have promised to reduce their carbon emissions by half by the year 2050.

collocation: reduce carbon emissions

Planting more trees helps absorb carbon from the atmosphere and slow down global warming.

collocation: absorb carbon

Common collocations
  • carbon emissions
  • carbon footprint
  • carbon tax
  • absorb carbon
  • produce carbon
  • reduce carbon
Synonyms
  • carbon dioxide

    the full scientific name for the gas; more precise, less common in headlines

  • greenhouse gas

    broader group including methane and nitrous oxide; used in policy contexts

Usage Note

In everyday speech and news reports, 'carbon' by itself almost always means carbon dioxide rather than the raw element. The sense is especially common in compounds such as 'carbon emissions', 'carbon tax', and 'carbon footprint'.

Common Mistakes

We need to reduce carbon in the air.' (vague)
We need to reduce carbon emissions.
When talking about climate change, specify what aspect of carbon you mean.

3. a duplicate of a typed or written document, produced by placing a specially trea

3.nounB2
Definition

a duplicate of a typed or written document, produced by placing a specially treated sheet between two ordinary sheets of paper so the pressure of writing transfers the ink to the bottom sheet

Example

Before computers were common, secretaries always kept a carbon of every letter they typed.

countable: a carbon (short for carbon copy)

Aiko found an old carbon of the contract in the filing cabinet from the 1980s.

Common collocations
  • make a carbon
  • keep a carbon
  • carbon of a letter
Synonyms
  • carbon copy

    the full form, more formal; also used figuratively for something very similar

  • copy

    more general word that works for both paper and digital replicates

Usage Note

Often shortened to just 'carbon', e.g. 'I made a carbon for my files.' This sense is now rare in everyday use because digital copying has replaced carbon paper. Learners should be aware of the meaning but will rarely need to produce it actively.

4. a thin sheet of paper with a dark coating on one surface, inserted between two p

4.nounB2
Definition

a thin sheet of paper with a dark coating on one surface, inserted between two pages so that writing pressure transfers the colour onto the lower page

Example

The old typewriter still worked, but Rohan could not find any carbon to put between the pages.

uncountable use: any carbon (any carbon paper)

The dark coating on carbon paper comes off on the sheet below, making a copy.

usage description: use carbon paper

Common collocations
  • sheet of carbon paper
  • use carbon paper
  • piece of carbon
Synonyms

Usage Note

The short form 'carbon' is used interchangeably with 'carbon paper', e.g. 'I need a sheet of carbon.' Context usually makes clear whether the paper itself or the copy is intended.

Word family

Synonym discussion

Sense: noun/2

All three terms relate to climate change, but they differ in specificity. 'Carbon dioxide' is the full chemical name for the gas (CO₂); 'CO₂' is its scientific abbreviation, common in charts and reports. 'Carbon' alone is the shortest and most common in news headlines and everyday speech — 'carbon tax', 'carbon footprint'. 'Greenhouse gas' is broader: it includes methane, nitrous oxide, and others, so it is used in policy discussions that cover multiple pollutants. In daily conversation about climate action, 'carbon' is the most natural choice. For example, a person might say 'I want to reduce my carbon footprint,' not 'I want to reduce my greenhouse gas footprint.'

carbon dioxidegreenhouse gasCO₂

Common collocations

Nouns

  • carbon atom
  • carbon cycle
  • carbon content

Phrases

  • low-carbon economy
  • high-carbon fuels

Prepositions

  • carbon in
  • carbon from

Etymology

LatinFrenchEnglish

The word 'carbon' comes from the Latin word 'carbo', meaning 'coal' or 'charcoal'. It entered French as 'carbone' in the 18th century when scientists recognised it as a distinct element, then passed into English. The chemical symbol C was adopted at the same time.