Definition of billboard

Advertising: 12' X 25' structure used for outdoor advertising. The billboard, or poster panel, is usually anchored in the ground, although it may be affixed to a wall or roof, in an area of high traffic volume. In the advertising industry, a billboard is actually termed a poster because the advertiser's message is printed on large sheets of poster paper that are then mounted by hand on a panel. Poster sizes are referred to in terms of sheets. Originally a billboard required 24 of the largest sheets a printing press could hold; thus a billboard is often called a 24-sheet. (Although press sizes have changed and the advent of the computer offers many unique size options, the term 24-sheet is still used.) Billboard advertising has the advantages of ready communication of simple ideas, repeated exposure to a message, and promotion for locally available products. Typically it is used in support of advertising campaigns using other media or to achieve long-term exposure. Relatively low in cost, billboard advertising accounts for approximately 1% of all advertising expenditures.
Broadcast: 10-second announcement at the beginning or end of a broadcast that identifies a sponsor or lists the cast of a program. See also painted display.