non-metallic element occurring naturally as diamond, graphite, or charcoal, 1789, coined 1787 in French by Lavoisier as charbone, from Latin carbonem (nominative carbo) "a coal, glowing coal; charcoal," from PIE root *ker- (3) "heat, fire."

Carbon 14, the long-lived radioactive isotope used in dating organic deposits, is from 1936. Carbon-dating (using carbon 14) is recorded from 1958. Carbon cycle is attested from 1912; carbon footprint was in use by 2001. Carbon-paper "paper faced with carbon, used between two sheets for reproduction on the lower of what is drawn or written on the upper" is from 1855, earlier it was carbonic paper (1850).

late 14c., "part of a curved line," originally in reference to the sun's apparent motion across the sky, from Old French arc "bow, arch, vault" (12c.), from Latin arcus "a bow, arch," from Proto-Italic *arkwo- "bow."

This has Germanic cognates in Gothic arhvazna, Old English earh, Old Norse ör "arrow," from Proto-Germanic *arkw-o- "belonging to a bow." It also has cognates in Greek arkeuthos, Latvian ercis "juniper," Russian rakita, Czech rokyta, Serbo-Croatian rakita "brittle willow." De Vaan sees an Italo-Germanic word for "bow" which can be connected with Balto-Slavic and Greek words for "willow" and "juniper" "under the well-founded assumption that the flexible twigs of juniper or willow were used as bows." The Balto-Slavic and Greek forms point to *arku-; "as with many plant names, this is likely to be a non-IE loanword."

The electrical sense is attested from 1821.

1882, in the electrical sense, from arc (n.). Meaning "to move in an arc" is attested by 1940. Related: Arced; arcing.

1895, from carbon (paper) + copy (n.). A copy on paper made using carbon-paper (paper faced with carbon, used between two sheets for reproduction on the lower of what is drawn or written on the upper). The figurative sense is from 1944. Also as a verb, "send a carbon copy (of something)," and as such often abbreviated c.c.

1869, so called because it consists of one carbon and two oxygen atoms. The chemical was known since mid-18c. under the name fixed air; later as carbonic acid gas (1791). "The term dioxide for an oxide containing two atoms of oxygen came into use in the middle of the 19th century." [Flood].

"carbon-14," a radioactive isotope of carbon, 1940, from radio-, combining form of radioactive, + carbon. Radio-carbon dating is attested from 1949 (the carbon-14 in organic matter decays at a known rate from the time of death).

1869, so called because it consists of one carbon and one oxygen atom (as opposed to carbon dioxide, which has two of the latter). An older name for it was carbonic oxide gas.

"light produced by an electric arc," 1871, from arc (n.) + light (n.). Related: Arc-lamp.

"of or pertaining to carbon," 1791, from carbon + -ic.

"compound of hydrogen and carbon," 1800, from hydrogen + carbon. Related: Hydrocarbonaceous; hydrocarbonous (1788).