carbon copy

n. (cc, abbr.) A copy of a document made at the same time as the original through the use of paper coated with a pigment (originally carbon) that is transferred to another sheet from the pressure of a pen or typewriter.

Notes

It is possible to make several copies simultaneously by adding more layers of carbon paper and regular paper. The quality of subsequent copies is reduced because the pressure is more diffuse, making the impression less sharp. Carbon paper was invented by Ralph Wedgewood in the 1800s in England, and was available in the United States by the 1820s. Because the copying technique did not work well with the quill pens of the time, carbon copies did not become common until the introduction of the typewriter.

Citations

Yates 1989, p. 45 Carbon paper soon replaced the letter press for making routine file copies, while various sorts of duplicators provided, for the first time, rapid and inexpensive methods of mass reproduction.