A thumbtack is a short pin with a flat, round head that you can push into a wall or bulletin board with your thumb. The wide head makes it easy to press in without hurting yourself, and the sharp point on the other end pokes through paper and holds it in place.

You've probably seen thumbtacks holding up artwork in classrooms, pinning notices to cork boards, or securing maps to walls. They're designed so you can put them up and take them down easily without tools. When you press the flat top with your thumb, the point slides into a soft surface like cork or drywall, and when you need to remove what you've posted, you can pull the thumbtack out just as simply.

Some people call them pushpins, though pushpins sometimes have longer plastic handles instead of flat metal heads. The beauty of a thumbtack is its simplicity: it's been doing the same job for over a hundred years, holding up everything from spelling tests to family photos to reminder notes.

Be careful with thumbtacks, though. The point is sharp, so keep them off the floor and out of your mouth, and pick them up right away if you drop one.