/ ˈfɔːti; NAmE ˈfɔːrti/
1.
number 40
2.
noun the for·ties [ pl. ] numbers, years or temperatures from 40 to 49
► fortieth / ˈfɔːtiəθ; NAmE ˈfɔːrt-/ ordinal number , noun
HELP NOTE : There are examples of how to use ordinal numbers at the entry for fifth .
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IDIOMS
- in your forties
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WORD ORIGIN
Old English fēowertig (from four and -ty ).