(noun)
a counter or room in a restaurant, hotel, or commercial establishment where alcoholic beverages and other refreshments are served, or an establishment dedicated to this purpose;
e.g. They decided to meet at a bar in the city.
(noun)
something that serves as a restriction, obstacle, or barrier to a thing or an action;
e.g. There is no bar on the number of books you can borrow from the library at a time.