Thumbtack (noun)

1. A small, pointed metal or plastic fastener, used especially for attaching papers to a bulletin board or wall.
2. A simple, inexpensive item used to secure papers, posters or artwork to a bulletin board or wall.

Origin:

From thumb + tack.

Examples:

1. She used a thumbtack to hang the picture on the wall.
2. He had a collection of thumbtacks in various shapes and colors.
3. The thumbtack was the perfect size for hanging posters in his dorm room.
4. The teacher used a thumbtack to attach the students' work to the bulletin board.
5. The thumbtack was a convenient tool for displaying information in the office.