Coupling

Coupling means how well two things are connected or work together. Imagine playing with blocks- sometimes you stack them really well so they don't fall down easily, but other times you stack them quickly and they fall over. The better the blocks are stacked, the better they are "coupled".

The same thing can happen with machines or things we use every day. For example, when you use a screwdriver to turn a screw, you want them to be "coupled" effectively- meaning you want the screwdriver to fit right into the screw so you can turn it without it falling out or turning the wrong way.

When things are not coupled well, they can break or not work right. So, it's important to make sure things are connected well and work together effectively.