A tumbler is a stem-less, often flat-bottomed drinking vessel, which is typically taller than 3 inches, and has no handle.
It would seem that the word ‘tumbler’ has been in circulation since the 17th Century. Initially, it was used to describe a metal cup with a round bottom. When the tumblers were placed on the table, they would ‘tumble’ around, due to the rounded bottom. It has been suggested that this was an intentional practice in order to sell more alcohol, as the drinker couldn’t put the tumbler down until they had finished their drink. However, it is more likely that this intentional rounded base was instead crafted to aid with travelling. The rounded base of a tumbler meant that during a journey in a coach or (later) train, the cups would maintain their balance.