‘Postal stationery’ as a philatelic term refers to envelopes, cards etc that have a stamp directly printed onto them to pay the postage. As has often been noted, this was Rowland Hill’s original idea for implementing prepayment for Penny Postage, with adhesives being something of an afterthought.
A minute of 26 December 1839 that named the winners of the ‘Treasury Competition’ directed that four different kinds of postage stamps should be prepared: stamped covers and stamped envelopes (the Mulready letter-sheets and envelopes), adhesive stamps (you may have heard of these somewhere), and . This last was what is referred to as ‘stamped to order’ (STO) in a GB context
