A clamp is a tool that helps you hold something in place. Imagine you are building a tower out of blocks. You want to make sure the blocks don't fall over while you're stacking them. A clamp is like a giant hand that can hold the blocks tight so they don't move.
Clamps have two parts: a handle and a jaw. The handle is like a lever that you push or pull to make the clamp open or close. The jaw is the part of the clamp that actually holds onto the thing you want to clamp.
Some clamps are made for big things, like holding a piece of wood or metal steady while you saw or drill into it. Other clamps are made for small things, like holding a piece of paper still while you glue something onto it.
Clamps come in all shapes and sizes. Some clamps look like giant tongs, while others look like little clips. But no matter what they look like, they all help you hold things still while you're working on them.