What's the difference between "package" and "module"?

Java Platform Module System or JPMS was introduced when java-9 was released. Starting from that time Java has both packages and modules. So what is the difference between them?

What is a Package?

A package is a namespace that organizes a set of related classes and interfaces.

What is a Module?

A module is a collection of related Java packages and associated resources with a descriptor file, which contains information about which packages/resources are exposed by this module, which packages are used by current module and some other information.

We can thing of a Java Module as a higher level of aggregation above packages. A Module allows you to organize a few packages into one single logical unit and to distribute them as one whole system. As well JPMS provides a way to control which packages are visible to users.