Pressure is like when you put a lot of stuff in a small space and it gets really squished. Imagine you and your friend are trying to fit into a small box, you'll feel very squished and squeezed, right?
Pressure measurement means we're trying to figure out how squished something is. But instead of measuring it with our hands or eyes, we have special tools that can tell us how hard the stuff is pushing against them.
For example, a tire gauge measures the pressure of the air inside a tire so we know if it's too low or too high. A barometer measures the pressure of the air outside, which can tell us if it's going to rain or be sunny.
People use pressure measurement to do lots of different things, like making sure airplanes can fly safely or that the pressure in a factory machine is just right. It's important because if the pressure is too high or too low, things can break or not work the way they should.