Duplication (noun)

1. The act of making a copy or duplicate of something.
2. The production of two or more copies of the same material.
3. The state of being duplicated or repeated exactly.

Origin:

Late 16th century: from french duplication or latin duplicatio(n-), from duplicare 'to double', from duo 'two' + plicare 'to fold'. the verb dates from the early 17th century.

Examples:

1. The duplication of the keys is a simple process that can be done at a hardware store.
2. The duplication of the film was done in order to preserve the original for posterity.
3. The duplication of the genetic material is an essential process for cell division.
4. The duplication of the paintings was discovered when the experts compared the works side by side.
5. The duplication of the melody in the chorus makes the song more memorable and catchy.