Cargo is stuff that people want to move from one place to another place. It can be anything, like toys, food, furniture or even cars.
Imagine you have a handbag that you want to take to your friend's house. That handbag is a small cargo because it's something that you want to take with you. You can carry it in your hands or on your shoulder because it's not too heavy. But, what if you have many handbags and they are too heavy to carry all at once? That's where a cargo truck comes in!
A cargo truck is like a big car that's used to transport things from one place to another. It's designed to be able to carry heavy things that can't be carried by one person. Just like you can put things in your backpack, people put things in the back of the cargo truck. The back of the truck is called the "cargo hold".
When people have a lot of things to move, they hire a cargo company to help them move it. The cargo company will send a big truck to their house, and the people will pack their things into the cargo hold of the truck. Then, the cargo truck will drive to the new place, and the people can unpack their things.
So, in summary, cargo is just a fancy word for the stuff that people want to move from one place to another, and a cargo truck is like a big car that helps move all that stuff.