A copy made with carbon paper WordNet 3.0 & Open English WordNet

Before the development of photographic copiers, a carbon copy was the under-copy of a typed or written document placed over carbon paper and the under-copy sheet itself. Wikipedia

Simple document copying technique, as well as a header in e-mail. Wikipedia Disambiguation

Technique of producing one or more copies simultaneously Wikidata

A sheet of carbon paper. Wiktionary

Informal: a sheet of carbon paper. Wiktionary (translation)

A copy produced in an alternated stack of ordinary sheets of paper and carbon papers. The pressure applied on the top sheet (by a pen or typewriter) causes every carbon paper to release its carbon cover, thus reproducing the writing on the subjacent layers of paper. Wiktionary

A copy. Wiktionary (translation)