A self-service grocery store. Basically any modern grocery store is a groceteria; you pick the food off of the shelves yourself, and you're lucky to get your bags carried to you car, never mind delivered to your house.
This term is now pretty much obsolete, due to the roaring success of the concept it referred to. (Groceterias you may be familiar with include Trader Joe's, Safeway, Ingles, Lowes, Aldi, Piggly Wiggly, Kroger, Food Lion, A&P, and Red & White). Nowadays we use 'supermarket', 'grocery store', or just 'grocery'. Groceteria is still used occasionally when a writer is trying to be quaint or old-fashioned.
I came across this word while looking for a definition for 'grocerateria'. I have not found one yet, although it appears to mean the same as groceteria. If you have any more information regarding this word, please /msg me.