a printed illustration on a large sheet.
a large, flexible sheet bearing text, usually illustrated, that is publicly displayed to advertise or promote something.
A poster1 is usually mass-produced and intended to be hung as decoration.
LoC 2007, p. 540 Single or multi-sheet notices made to attract attention to events, activities, causes, goods, or services; also, purely decorative posters. For posting, usually in a public place; chiefly pictorial. Intended to make an immediate impression from a distanc