Okay kiddo, have you ever seen a big box that people use to move things from one place to another? It's called a container. And when these containers are brought to a place near the water, where very big ships can come and go, we call it a container port.
It's like a playground for these big ships, where they can park next to the shore and unload or load lots of containers at a time. The people who work at the container port help the ships and the containers move around, find their way and make sure everything stays safe.
When the ships are full of containers, they sail away to another country or city, where someone else takes care of them. It's like sending a present to someone far, far away. And the container port is the place where everything starts and ends for these big containers.