To supply a backup in case the original is destroyed.
Duplicate
Mitosis
If you are referring to copies of files that get saved to different folders on your hdd or ssd by accident or on purpose, they are called duplicate files or exact duplicates. People use programs called duplicate finders, such as Easy Duplicate Finder, Auslogics Duplicate File Finder and Gemini, to delete duplicate files.
The term "carbon copy" originates from the practice of creating duplicate copies of typed or written documents using carbon paper. Carbon paper was placed between the original document and a blank sheet of paper, so that when the original was written or typed on, the pressure transferred the ink or impressions onto the underlying sheet, creating an exact copy. The term "carbon copy" later came to be used metaphorically to mean an exact or identical duplicate of something.
"Return in duplicate" means to provide two identical copies of a document or form. One copy is typically retained by the sender or issuer, while the other copy is kept for the recipient or for filing purposes.
In contect DUP will normally indicate a "DUPLICATE"
Backup
multiple master replication
The word that means four copies is "quadruplicate." It is derived from the Latin word "quadruplicare," which means to make fourfold or to duplicate four times. In various contexts, it can refer to documents or items that are produced in four identical copies.
Blind carbon copy notation is a device used by the writer he sends duplicate copies to the others.
A carbon copy is made by using carbon paper. Carbon paper is a very thin sheet of paper coated on one side with a film of carbon in suspension. The carbon paper is placed between two sheets of paper when intending to write or type (with a typewriter) on one of the sheets and to produce a duplicate of the writing on the second sheet of paper. It is important to have the carbon side of the carbon paper resting on the paper that will be the duplicate. The term "carbon copy" (abbreviated cc) is used to indicate the duplicate. Now, when it is possible to create duplicate copies by other means, the term "carbon copy" continues to be used to refer to the duplicate copies.
Usually institutions will not issue duplicate certificates - to prevent fraud. They normally provide a letter confirming the persons qualifications with the institution where/when this is needed.