A fuel dispenser is what you see at gas stations where the gas comes out of. It's kind of like a giant straw that pumps gas out of an underground tank and into your car's gas tank.
When you pull up your car next to a fuel dispenser, you'll see a big metal box with a hose and nozzle on it. That's the fuel dispenser. Inside the metal box, there's a whole bunch of pipes and tubes that are used to measure how much gas you're getting and to make sure that only the right amount of gas goes into your car.
When you pay for your gas at the pump, the fuel dispenser will automatically start pumping gas into your car's gas tank. You can control how much gas you get by squeezing the handle on the nozzle. If you squeeze the handle a little bit, you'll get a little bit of gas. If you squeeze the handle all the way, you'll get a lot of gas.
Once you're done getting gas, the fuel dispenser will automatically shut off to let you know that your car's gas tank is full. Then you can drive away and enjoy your newly filled-up tank of gas!