Block.—A number of stamps not torn apart. A strip of stamps and a number of stamps forming an odd shape are, however, not considered as blocks.
Chalk-Surface.—A surface given to stamps by means of a preparation of chalk, in order that obliterations may not be cleaned out.
Commemorative Stamps.—Stamps issued to remind people of bygone events.
Control Letters.—Letters on the margin paper of sheets of stamps, for official purposes of control.
Entire.—A postcard, wrapper, or envelope complete as it has passed or would pass through the post—i.e., not the stamp cut from it.
Error.—A stamp which contains some faulty workmanship, of whatever kind.
Facsimile.—See Forgery.
Forgery.—An unofficial stamp, one made in order to cheat. In cases where a real stamp is given an unauthorized overprint (which see), the stamp constitutes a forgery.
Hinges.—The papers gummed on one surface used for fixing stamps to the album.
Imperforate.—Stamps that are not provided with perforated margins to facilitate separation.