tum ‧ bler /ˈtʌmblə $ -ər/ BrE AmE noun [countable]
[ Date: 1300-1400 ; Origin: tumble ; ]
[ Sense 1-2: Origin: because it was originally made with a round or pointed bottom ]
1 . a glass with a flat bottom and no handle
2 . ( also tumblerful /-fʊl/ British English ) the amount of liquid that this type of glass can contain
3 . old-fashioned someone who performs special movements such as doing ↑ somersault s (=a jump in which you turn over completely in the air) SYN acrobat