a carbon copy
1. A copy of a document that is made by placing a sheet of carbon paper under the original so that the print gets transferred from the original to the sheet of paper below it. Carbon copies are largely obsolete but are still used in some cases for receipts. Could you please make a carbon copy of that invoice? I need it for my records.
2. To include additional recipients on an email message that is intended for, or directed to, another person. Often abbreviated as "cc." Please carbon copy me on that email to Janice. I want her to know I am aware of the situation.
3. A person or thing that closely resembles someone or something else in looks or attributes. Even though they were born several years apart, Darren is a carbon copy of his brother. They have the same gait, mannerisms, and hairstyle.
a carbon copy
COMMON If one person or thing is a carbon copy of another, the two people or things are identical, or very similar. Hugh was a carbon copy of his father, Edward; both had the same blond hair and easy charm. The town, almost a carbon copy of Gualdo, is best known for its mineral waters. Note: A carbon copy of a document is an exact copy of it which is made using carbon paper.
a ˌcarbon ˈcopya person or thing that is exactly or extremely like another: The recent robberies in Leeds are a carbon copy of those that have occurred in Halifax over the last few months.
A carbon copy is a copy of a document, letter, etc. made by placing carbon paper (= thin paper with a dark substance on one side) between two sheets of paper.