What is Python Package?

Python packages organize related modules into a directory hierarchy. A package is a directory containing an __init__.py file (which can be empty) and one or more .py module files. Packages can be nested (subpackages). Distribution packages are installable units shared via PyPI using pip. Modern packaging uses pyproject.toml (PEP 518) with build backends like setuptools, Poetry, or Flit. The packaging ecosystem includes wheels (.whl) for pre-built distributions, sdists for source distributions, and dependency resolution tools. Understanding packages is essential for creating reusable, distributable Python code.