The Old fashioned glass, rocks glass, or "lowball", is a short tumbler used for serving liquor "on the rocks", meaning over ice, or cocktails having few ingredients. It is named after the Old Fashioned cocktail, traditionally served in such a glass.
Contemporary American "Old Fashioned" and "rocks" glasses may hold as much as 8-12 ounces, and may be used to serve a wide variety of beverages over ice.