series of <#defin=definitive>  <#defin=stamps> that began in 1975.  The first <#scott=Scott> # is 1581.

one in a series of international stamp shows hosted once every decade in the U.S.  Ameripex ’86 was held in Chicago in 1986.  A <#stamp> (<#scott=Scott> 2145), <#souvenir=souvenir sheets> (<#scott=Scott> 2216-2219) and an <#ampc=Air Mail Postal Card> (<#scott=Scott> UXC23) were issued in conjunction with this show.

a seven color <#gravure> press installed at the <#bep=BEP> in 1970. The first <#stamp> printed by this press was the 1971 Missouri Statehood Issue (<#scott=Scott> 1426).  In addition to stamps this press also produced <#aerogram=aerograms>.

a <#fugink=fugitive ink> made with synthetic organic pigments produced as derivatives of nitrobenzene.  Aniline ink was used in the production of stamp ink from before the <#washfrank=Washington-Franklin> era until its importation from Germany became impossible during World War I.  When inferior quality aniline ink was used, bleeding of pigment resulted in stamps known as <#pink=pink backs>.  Aniline ink was also used to <#surcharge> some <#revenue> stamps.

(formerly Army Post Office)  A U.S. post office established for military units overseas.  APOs, as they are called, first established in 1917, are designated by a number.