see <#dummy=Dummy Stamps>.

see <#dummy=Dummy Stamps>.

stamp-like <#label=labels> either without <#denom=denomination> or with a value shown that has a defacement line through it.  Such stamps were used for training and testing purposes.  Produced in <#sheet>, <#coil> and <#booklet> format.  These "stamps" have no postal value or validity.

1) a single unit <#handstamp> uniting both a <#postmark> and a <#cancel>.  First introduced in the 1860s and in use through the 1940s.  2) the impression left by a duplex cancel handstamp on a <#cover>.

abbreviated term for Durland Standard Plate Number Catalog, the authoritative catalog of <#pn=plate numbers> originally published by Clarence Durland beginning in 1950, and now edited and published by the <#usss=United States Stamp Society>.