A software package is a unit of software distribution or installation, typically containing code, associated files and metadata describing its identity, version and software dependencies. It may contain an application, several software libraries or supporting data. The exact packaging format determines which metadata and installation operations are available.
For example, installing a numerical application can also require installing a compatible array software library. Pip reads requirements from Python distribution files and uses dependency resolution to choose compatible versions.[ref]
Dependency Resolution in the pip documentation. How it works, distribution files and recursively discovered requirements
One distribution unit need not correspond to one importable module. Distinguishing the shipped artifact from the names imported by code avoids assuming that every import name is also an installable package name. New to topics? Read the docs here!