the decade from 1950 to 1959, or the years when someone is between 50 and 59 years old, or the numerical range of 50 to 59.
From 'fifty' (from 'five' + 'ten', Old English origins) + '-ies' (plural). This is a straightforward compound referring to groups of fifty.
The 1950s Fifties were such a distinctive cultural moment—rock and roll, the space race, suburban expansion—that 'the Fifties' instantly evokes a specific aesthetic and mood, making it one of the most brand-able decades in modern history.
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