thir·ty /ˈɵɚti/ noun, pl-ties 1[count] : the number 30 2thirties[plural] a : the numbers ranging from 30 to 39 • The temperature outside is in the high thirties. b : a set of years ending in digits ranging from 30 to 39 • He is in his thirties. • old photographs from the thirties [=from 1930–1939]
- thir·ti·eth /ˈɵɚtijəɵ/ noun, pl-tieths[count] • the thirtieth of November • seven thirtieths of a degree
- thirtiethadj • her thirtieth birthday
- thirtyadj • thirty days/dollars
- thirtypronoun • thirty of his classmates
- thir·ty·ish /ˈɵɚtijɪʃ/ adj • He was tall, thirtyish [=about 30 years old], and had glasses and brown hair.