carboncopy
Carbon copy, also known as CC, is a method of duplicating a document, typically a letter or a photograph, onto multiple copies simultaneously. The phrase "carbon copy" is derived from a device that produces duplicates of written or printed material, known as a carbon paper.
When an original piece of writing is typed or printed, a sheet of carbon paper is placed
The use of carbon paper was widespread until the introduction of copy machines and electronic document reproduction
In online communication, carbon copy has a different connotation, referring to the ability to easily share