Back Stamp : A postmark applied to the back of a letter on 'arrival'.

Bantams : The smaller sized stamps issued by South Africa during WWII to conserve paper.

Bar code : A series of vertical full bars and half bars representing the ZIP Code information printed on a mail piece to facilitate automated processing by bar code reader equipment.

Bisect : A stamp which is cut in half, usually diagonally. Often used when stamps are in short supply.

Blind Perforation : A perforation which has not been punched out due to a broken, blunt or missing pin in the comb.

Block of stamps : A group of 4 or more stamps which are not separated.

Booklet : A folder containing stamps, either definitive or commemoratives and issued by the postal authorities.

Booklet Pane : A small sheet of stamps specially cut to be sold in booklets.

Bogus : A completely fictitious, worthless "stamp," created only for sale to collectors. Bogus stamps include labels for nonexistent values added to regularly issued sets, issues for nations without postal systems, etc.

Bourse : A marketplace, such as a stamp exhibition, where stamps are bought, sold, or exchanged.