This is the 277th most frequent Polish word.
pół
"Half."
The word "pół" is used to denote 'half' of a certain quantity or object, in this case, 'half a glass'.
Mam pół szklanki wody.
I have half a glass of water.
Here, "pół" is employed to signify 'half' of a temporal unit, specifically 'half an hour'.
Spotkamy się za pół godziny.
We will meet in half an hour.
In this context, "pół" means 'half' of an item being divided, in this case, a pizza.