A prison officer is someone who works in a place where people who have broken the law are sent to live as punishment. This place is called a prison, and it's like a big, safe building where the people who broke the law live away from the rest of the community.
The job of a prison officer is to make sure that the people who live in the prison are safe, and that they follow the rules so they don't get into any more trouble.
They help the prisoners with things like getting medical care if they need it, making sure they have enough food to eat and clean clothes to wear, and making sure they have a place to sleep at night.
Prison officers also make sure that the prisoners don't hurt each other or the people who work at the prison. They might do things like search the prisoners to make sure they're not hiding anything dangerous, or keep an eye on them while they're working or exercising so they don't start any fights.
Overall, the job of a prison officer is to make sure that everyone is safe and following the rules so that the prison can be a good place for people to live while they're being punished for breaking the law.