The philatelic use of the word gutter is the space left between postage stamps which allows them to be separated or perforated. When stamps are printed on large sheets of paper that will be guillotined into smaller sheets along the gutter it will not exist on the finished sheet of stamps. Some sheets are specifically designed where two panes of stamps are separated by a gutter still in the finished sheet and gutters may, or may not, have some printing in the gutter. Since perforation of a particular width of stamps is normal, the gutter between the stamps is often the same size as the postage stamp.

Several derivative terms exist: 
Gutter pairs are two stamps separated by a gutter.
Gutter block is a block of at least four stamps where either the vertical or horizontal pairs, or both, are separated by a gutter.
Gutter margin is a margin dividing a sheet of stamps into separate panes.

However with modern high technology of printing, processing and perforating, Miniature Sheets and Sheetlets are printed with gutter margins within these sheets. These gutter margins do join the two stamps vertically, horizontally or in some zigzag manner. These margins also have some printing which may or may not form the part of the total picture-design of the sheet. Here, an effort is made to present such FDCs with Gutter Margins from Miniature Sheets and Sheetlets. presented. In these FDCs one can see some printed portion on the gutter portion which may or may not form the part of the main picture. Such covers are made with creative imaginations of the philatelists.

Gutter margins of stamps on FDCs & Folders are shown with the arrow marks.