As nouns the difference between filling and milling
is that
filling is anything that is used to fill something while
milling is the series of notches around the edge of a coin, placed there during minting so that it can be told if some of the metal from the edge is removed removing metal from a coin was common practice during earlier times when coins made of precious metals circulated.
As verbs the difference between filling and milling
is that
filling is while
milling is .
As an adjective filling
is of food, that satisfies the appetite by filling the stomach.