A poster is a form of printed communication used to advertise or promote a product, service, event, or idea. The term 'poster' can refer to a variety of printed materials, including handbills, circulars, affiches, advertisements, cards, announcements, banners, billboards, notices, bills, placards, and signs. Handbills are small, printed flyers that are distributed by hand. Circulars are similar to handbills but are usually distributed by mail. Affiches are large posters that are often used for advertising. Advertisements are printed messages that are used to promote products or services. Cards are small, printed messages that are often used for invitations or announcements. Announcements are printed messages that are used to inform people about upcoming events. Banners are large, printed messages that are often hung from walls or ceilings. Billboards are large, printed messages that are often displayed outdoors. Notices are printed messages that are used to inform people about important information. Bills are printed messages that are used to request payment for goods or services. Placards are large, printed messages that are often used for advertising. Signs are printed messages that are often used to indicate directions or provide warnings.