miniature sheet

A souvenir sheet or miniature sheet is a small group of postage stamps still attached to the sheet on which they were printed. They may be either regular issues that just happen to be printed in small groups (typical of many early stamps), or special issues often commemorating some event, such as a national anniversary, philatelic exhibition, or government program. The number of stamps ranges from one to about 25; larger sheets of stamps are simply called "sheets" with no qualifier.