Stopping at the store or usually a quickie mart to grab and throw down some snacks while on your way to eat at someone's house. Usually because you know there's going to be little or no good food there.
(dinner at mom's)
We better stop and grab some store d'oeuvres, you know that mom never has enough food.
(on the way to a party at some chick's house)
Jim: Isn't she a vegetarian? We'd better stop and get some store d'oeuvres. I can't eat that shit all night.