a <#postalmark=postal marking>, usually applied to the back of a <#cover>, evidencing either the arrival of a cover at its destination post office or the handling of a cover while in transit.  Applying a backstamp to <#firstclass=First Class Mail> upon arrival at the destination post office was mandatory from 1879 until 1913.   The backstamping of ordinary air mail was discontinued in 1929.  See <#receiving=Receiving Mark> and <#tranmark=Transit Mark>.

a continuous narrow band of horizontal or vertical <#tagging> that extends across a <#pane> of <#stamp=stamps>.  Example: 1973 8¢ Postal Service Employees stamps, <#scott=Scott> 1489-1498.

private printer of modern <#stamp=stamps>, beginning with the 1992 29¢ Eagle & Shield, <#scott=Scott> 2595.

nickname for the <#stamp=stamps> of 1870-1894 produced by the <#nbnc=National Bank Note Co.>, <#cbnc=Continental Bank Note Co.>, and <#abnc=American Bank Note Co>.  The Bank Notes are sub-divided into <#largebn=Large Bank Notes> and <#smallbn=Small Bank Notes>.  Begins with <#scott=Scott> 134.

1.) a machine-readable code typically in the form of parallel lines of variable height or spacing sprayed in a row on the front or back of a <#cover> by the <#usps=U.S. Postal Service> or mailer.  The <#postnet=POSTNET> barcode is used to expedite the sorting and delivery of mail.  Other barcodes are used for tracing and tracking mail and are used in <#indicia> for security purposes.  2.) a machine-readable code used by the <#bep=BEP> as part of their Electronic Stamp Inspection process.  Barcodes are sprayed onto the margins of all <#coil> and <#booklet>  <#stamp=stamps> to facilitate the identification and removal of defective stamps.  While these bar codes are usually trimmed off in the manufacturing process, booklet panes do exist with a barcode on the <#tab>.