|1.||the circulation of carbon between living organisms and their surroundings. Carbon dioxide from the atmosphere is synthesized by plants into plant tissue, which is ingested and metabolized by animals and converted to carbon dioxide again during respiration and decay|
|2.||four thermonuclear reactions believed to be the source of energy in many stars. Carbon nuclei function as catalysts in the fusion of protons to form helium nuclei|
|a printed punctuation mark (‽), available only in some typefaces, designed to combine the question mark (?) and the exclamation point (!), indicating a mixture of query and interjection, as after a rhetorical question.|
|a calculus or concretion found in the stomach or intestines of certain animals, esp. ruminants, formerly reputed to be an effective remedy for poison.|
carbon cycle n.
In ecology, the movement of atoms of carbon through the biosphere. Molecules of carbon dioxide are taken in by plants, to be incorporated into their tissues, which may then be eaten by and incorporated into animals. Animals return the carbon to the air in the form of carbon dioxide, and the cycle starts again. (See photosynthesis and respiration.)