This is the 166th most frequent Italian word.
po
"Po" in Italian can mean "a little," "some," or refer to the Po River.
Here 'po'' is used as a short form of 'poco', meaning 'a small amount' or 'a little while'. It is employed to indicate a short measurement of time.
Aspetta un po', devo finire questa cosa.
Wait a bit, I need to finish this thing.
In this sentence, 'po'' again abbreviates 'poco' and is used to measure a small quantity of sugar in the context of a recipe.
Ho bisogno di un po' di zucchero per la ricetta.
I need a little bit of sugar for the recipe.
Here, 'po'' signifies a relatively short duration of time during which the action of watching the sunset occurred.