Definition:
A cut signature (also known as a cut sig) is a card containing an autograph that was cut from another document or piece of cardboard. This technique is used by sports card companies to produce autographed cards of deceased athletes, but is also used for living athletes to give the companies more flexibility in card design.
Occasionally the opening, or window, on a cut signature card will not be large enough for the autograph it contains. Cut signatures obscured in this way are seen as less desirable by many collectors and will tend to fetch lower prices when they are sold on the secondary market.
Examples:
Utilizing a cut signature is the only way a company can make a current autographed card of Babe Ruth.