Flyers, business cards, letterhead an so on are not usually printed on sheets of paper of the size we see them every day. Printing firms use bigger sheets of paper that will contain more copies or pages of a certain publication, flyer and so on. These big sheets, called parent sheets, are then folded and cut as needed to give us the printed product in the final size, which is what we see.
There are different sizes of parent sheets as determined either by the North American sheet sizes or the ISO sizes (used especially in Europe).
