Cpython

CPython: The Reference Implementation CPython is the original, reference implementation of the Python programming language, written in C. It is the most widely used and thoroughly tested implementation, serving as the de facto standard against which all others are measured. When one downloads Python from the official python.org website, they are installing CPython. Its name derives from the fact that the core interpreter is written in C, and it compiles Python source code into intermediate bytecode, which is then executed by the CPython Virtual Machine (VM).