fif·ty 
(fĭftē)
(fĭftē)n.
1. The cardinal number equal to 5 × 10.
2. fifties
a. A decade or the numbers from 50 to 59: They began playing golf in their fifties. With the sunshine, the temperature reached the fifties.
b. often Fifties The decade from 50 to 59 in a century.
3. A fifty-dollar bill.
[Middle English fifti, from Old English fīftig; see penkwe in the Appendix of Indo-European roots.]
fifty adj. & pron.
- Indo-European root: deu-
- Indo-European root: deuk-
- Indo-European root: deuə-
- Indo-European root: dhegwh-
- Indo-European root: dheigh-
- Indo-European root: dher-
- Indo-European root: dhers-
- Indo-European root: dheu-
- Indo-European root: dheu-
- Indo-European root: dheub-
- Indo-European root: dheugh-
- Indo-European root: dheuə-
- Indo-European root: dhghem-
- Indo-European root: dhgh(y)es-
- Indo-European root: dhreg-
- Indo-European root: dhreibh-
- Indo-European root: dhreu-
- Indo-European root: dhugəter-
- Indo-European root: dhwer-
- Indo-European root: dhē-
- Indo-European root: dhē(i)-
- Indo-European root: dhēs-
- Indo-European root: dhīgw-
- Indo-European root: dlegh-
- Indo-European root: dn̥ghū-