/ ˈθɜːti; NAmE ˈθɜːrti/ number
1.
30
2.
noun the thirties [ pl. ] numbers, years or temperatures from 30 to 39
► thir·ti·eth / ˈθɜːtiəθ; NAmE ˈθɜːrt-/ ordinal number , noun
HELP NOTE : There are examples of how to use ordinal numbers at the entry for fifth .
•
IDIOMS
- in your thirties
••
WORD ORIGIN
Old English thrītig (from three and -ty ). The spelling with initial thi- is recorded in literature in the 15th cent., and has been the prevalent form since the 16th cent.