1. Symbol C An abundant nonmetallic element that occurs in many inorganic and in all organic compounds, exists freely in amorphous, graphite, and diamond forms and as a constituent of coal, limestone, and petroleum, and is capable of chemical self-bonding to form an enormous number of chemically, biologically, and commercially important molecules. Other significant allotropes include fullerenes and nanotubes. Atomic number 6; atomic weight 12.011; sublimation point 3,825°C; triple point 4,489°C; specific gravity of amorphous carbon 1.8 to 2.1, of diamond 3.15 to 3.53, of graphite 1.9 to 2.3; valence 2, 3, 4. See Periodic Table.
2. A carbon-containing gas, notably carbon dioxide, or a collection of such gases, especially when considered as a contributor to the greenhouse effect: plans for capturing and sequestering carbon produced by power plants.
a. A sheet of carbon paper.
b. A carbon copy.
a. Either of two rods through which current flows to form an arc, as in lighting or welding.
b. A carbonaceous electrode in an electric cell.
[French carbone, from Latin carbō, carbōn-, a coal, charcoal; see ker-3 in the Appendix of Indo-European roots.]
carbon·ous (-bə-nəs) adj.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2017 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
The American Heritage Dictionary Blog
Check out our blog, updated regularly, for new words and revised definitions, interesting images from the 5th edition, discussions of usage, and more.
American Heritage Dictionary Products
The American Heritage Dictionary, 5th Edition
The American Heritage Dictionary of Idioms
The American Heritage Roget's Thesaurus
Curious George's Dictionary
The American Heritage Children's Dictionary
The American Heritage Dictionary of Indo-European Roots
The American Heritage Student Grammar Dictionary
The American Heritage Desk Dictionary + Thesaurus
The American Heritage Science Dictionary
The American Heritage Dictionary of Business Terms
The American Heritage Student Dictionary
The American Heritage Essential Student Thesaurus