Note the operating system in the diagram.

Author: ericsnowcurrently

Doc/reference/executionmodel.rst

@@ -407,7 +407,7 @@ Python's execution model does not operate in a vacuum.  It runs on a
 computer.  When a program runs, the conceptual layers of how it runs
 on the computer look something like this::
 
-   host machine
+   host machine and operating system (OS)
      process
        OS thread (runs machine code)