carbon

1. The chemical element (symbol C) with an atomic number of 6. It can be found in pure form for example as graphite, a black, shiny and very soft material, or diamond, a colourless, transparent, crystalline solid and the hardest known material. (uncountable)
2. An atom of this element, in reference to a molecule containing it. (countable) · A methane molecule is made up of a single carbon with four hydrogens.
3. A sheet of carbon paper. (countable, informal)
4. A carbon copy. (countable, informal) · Please provide me with a carbon of your form.· Press firmly: you are making a carbon.
5. A fossil fuel that is made of impure carbon such as coal or charcoal. (countable, uncountable)
6. Soot. (countable, uncountable) · Every morning she cleaned the carbon from the lamp chimneys.
7. Especially, hardened soot as a caked-on deposit. (countable, uncountable) · When you overhaul an engine, you need to remove the carbon from around the valve seats. The carbon buildup can be extensive.
8. A carbon rod or pencil used in an arc lamp. (countable, uncountable)

Plural carbons