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.

see <#bia=Bureau Issues Association>.

service for a fee that provides a mailing receipt and maintenance by the <#usps=USPS> of a delivery record.  Certified Mail requires the signature of the recipient.  First offered in 1955.

the bits of paper removed in the <#perf=perforating> process.