The term “library” in Python is a broad concept referring to a collection of reusable code that provides specific functionality. There is no hard rule that says a library must contain multiple modules. If your module (i.e., a single file) encapsulates useful functionality, it qualifies as a library. Many popular libraries available on PyPI are, in fact, single modules. They are designed to be easy to install and use, regardless of the number of files they contain.