1) The edge of a roll, usually only part of the diameter, where the paper along that edge is thinner and longer than the balance of the width of the paper on the roll. To compensate for this extra length, it buckles as it is wound. 2) In the binding operation of making books, usually from dry paper, buckles can develop along the bound edge. The paper picking up moisture and increasing in dimensions, resulting in extra dimensions influencing durability causes this and corresponding poor appearance buckles being formed.