PyInstaller sets the sys._MEIPASS attribute to let the application know where to find its bundled resources. Source: this answer . I know what _MEIPASS does. What does the name _MEIPASS mean? What does it stand for? This was changed from an MEIPASS2 environment variable in version 2.0 . Nothing in the official documentation even alludes to the etymology of this variable. It appears to have been around since the beginning of PyInstaller.

What does "MEIPASS" stand for?

PyInstaller sets the sys._MEIPASS attribute to let the application know where to find its bundled resources. Source: this answer.

I know what _MEIPASS does. What does the name _MEIPASS mean? What does it stand for?

This was changed from an MEIPASS2 environment variable in version 2.0.
Nothing in the official documentation even alludes to the etymology of this variable.
It appears to have been around since the beginning of PyInstaller.