Tumbler (glass)
A tumbler is a flat-floored beverage container usually made of plastic, glass or stainless steel.
Theories vary as to the etymology of the word tumbler. One such theory is that the glass originally had a pointed or convex base and could not be set down without spilling. Another is that they had weighted bottoms which caused them to right themselves if knocked over.
The modern tumbler comes in various sizes and shapes, designed to accommodate a wide range of beverages from water and juice to sophisticated cocktails.