POLA can stand for principle of least authority or principle of least access. Basicly it is about not giving programs more authority/access than they need to run to do their intended job. No more and no less.
The canocial example is Solarite: an single player game of cards. The game only needs authority to open one window, draw to it, recieve events directed at that window and read write access to an file keeping the highscores. (Optionally read access to image files used as the tabletop, the front faces of the cards and the back face of the cards)