see <#pts=Postal Transportation Service>.

see <#canal=Canal Zone>.

unintended, lightly printed <#pn=plate numbers> found in varying locations in the <#margin=margins> of <#sheet=sheets> produced on the <#rotpress=rotary press>.  These are <#freak=freaks> caused by a <#setoff=set-off> that occurs when the dryer on the press is not operating at a warm enough temperature.

now independent country over which the U.S. exercised sovereignty from 1898 to 1946.  <#overprint=Overprinted> U.S. <#stamp=stamps> were used there beginning in 1899.  Beginning in 1906 the <#bep=BEP> printed stamps for use in the Philippines.

a color found on a rare variety of the 3¢ 1861 <#stamp> (Scott 64a).