From Longman Dictionary of Contemporary Englishtumblertum‧bler /ˈtʌmblə $ -ər/ noun [countable] 1 
DFUa glass with a flat bottom and no handle2 (also tumblerful /-fʊl/ British English)AMOUNT the amount of liquid that this type of glass can contain3 old-fashionedAP someone who performs special movements such as doing somersaults (=a jump in which you turn over completely in the air) SYN acrobat
DFUa glass with a flat bottom and no handle2 (also tumblerful /-fʊl/ British English)AMOUNT the amount of liquid that this type of glass can contain3 old-fashionedAP someone who performs special movements such as doing somersaults (=a jump in which you turn over completely in the air) SYN acrobatExamples from the Corpus
tumbler• The Gold Cadillac margarita is actually served in a tumbler over ice cubes with no salt anywhere to be seen.• The packet contained two smaller packets - one blue, one white, which were mixed together in a tumbler of water.• In both hands he held steady a glass tumbler drained to the ice.• The wine glasses, tumblers, pipes and so on were articles which each painter handled regularly in the course of day-to-day life.• I stand three feet from the glassware and count the tumblers lined up on a towel.Origin tumbler 1. (1300-1400) tumble; 2. because it was originally made with a round or pointed bottom 