Craft beer is a term that can only be loosely defined. It generally refers to a brewery that emphasizes quality rather than quantity, though many craft brewers do produce prodigious quantities of beer.
Beer Advocate defines craft beer as "Beer brewed in limited quantities often using traditional methods."
The term came into use to replace microbrew, which became a misnomer when describing large craft brewers like Anchor or Samuel Adams. It is generally used as a contrast to a macro beer, such as Budweiser (Anheuser-Busch), Coors, or Miller.