CC

A common abbreviation of "carbon copy". A carbon copy, in email terms, is sending an exact copy of an email (hence "carbon copy") to another person besides the main recipient(s). It differs from simply forwarding or putting another person in the "to" section in that it indicates they are simply passive readers, and not the main subjects intended to respond. The term stems from when a sheet of carbon was placed between a document and a blank piece of paper. A pen or pencil was pressed down on the fresh sheet of paper to make an exact copy of the original piece of writing. Now it is simply used metaphorically.