for ‧ ty /ˈfɔːti $ ˈfɔːrti/ BrE AmE number
[ Language: Old English ; Origin: feowertig , from feower 'four' ]
1 . the number 40
2 . the forties ( also the '40s, the 1940s ) [plural] the years from 1940 to 1949:
The place was built as a casino in the forties.
the early/mid/late forties
He spent several years in Paris in the late forties.
3 . be in your forties to be aged between 40 and 49
early/mid/late forties
The woman was probably in her mid forties.
4 . in the forties if the temperature is in the forties, it is between 40 degrees and 49 degrees
in the low/mid/high forties
The temperature was up in the high forties.
—fortieth adjective :
her fortieth birthday