horizontal line in the right <#margin> of a <#sheet> at the end of the horizontal sheet <#gutter> that was used by the <#eleceye=electric eye> in the <#perf=perforating> process.  First used experimentally in 1933.

a <#stampenv=stamped envelope> produced by the <#emboss=embossing> process.  Example: New York World’s Fair Issue, <#scott=Scott> U546.

largest private philatelic library in the United States, with extensive resources for researchers and collectors.

largest <#philatelic> organization in the United States.

major manufacturer of <#canmach=cancelling machines> in use from the 1880s to the 1940s.  This company is known for its <#flagcancel-gen=flag cancels>.