Billboard (noun)

1. A large flat surface, such as a board or a sign, used for displaying advertisements, usually along a road or highway.
2. A large sign or poster used for advertising.

Origin:

The word billboard comes from the combination of the words "bill" meaning advertisement or notice and "board" meaning a flat surface, so billboard means a large flat surface used for displaying advertisements.

Examples:

1. The billboard advertised the new movie that was coming out.
2. The company rented a billboard on the highway to advertise their product.
3. The billboard was so big that it could be seen from far away.
4. The artist painted a mural on the billboard.
5. The billboard was illuminated at night for better visibility.