A crutch is a support device that helps someone walk when they've injured their leg or foot. Crutches are usually tall poles that fit under your armpits, with handles to grip partway down. They let you move around without putting weight on an injured leg while it heals. You might see a classmate using crutches after breaking an ankle in soccer or spraining a knee on the playground.

The word also describes something people rely on too heavily instead of developing their own abilities. A student might use a calculator as a crutch instead of learning to do mental math. A speaker might lean on notes as a crutch rather than really knowing the material. In this sense, a crutch is something that props you up but can keep you from getting stronger on your own.