Crosshead

A crosshead is a part that helps keep a piston moving back and forth in an engine or a machine. It's like a little helper that keeps things running smoothly. Kind of like when you're trying to push a toy car across the floor, but it keeps getting stuck. If you attach a helper - like a little wheel or roller - to the bottom of the car, it can move more easily without getting stuck. That's kind of what a crosshead does in an engine or a machine. It helps the piston move freely so everything can work properly. It's a very important part of many machines and engines.