Proof
A proof refers to a sample version of a printed project created before the final print run, which allows authors, designers, or clients to review how the book is going to look like, and checking for issues in layout, color accuracy, image quality, margins, and content. Proofs helps to discover any mistakes before mass production begins, and can be printed digitally or via offset, depending on the final production method.

Proof is a sample to ensure the accuracy of final version