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: lei-
- Indo-European root: leid-
- Indo-European root: leig-
- Indo-European root: leigh-
- Indo-European root: leikw-
- Indo-European root: leip-
- Indo-European root: leis-
- Indo-European root: leis-
- Indo-European root: leit-
- Indo-European root: lendh-
- Indo-European root: leu-
- Indo-European root: leubh-
- Indo-European root: leudh-
- Indo-European root: leugh-
- Indo-European root: leuk-
- Indo-European root: leu(ə)-
- Indo-European root: lē-
- Indo-European root: līk-
- Indo-European root: lī̆no-
- Indo-European root: lūs-
- Indo-European root: mag-
- Indo-European root: magh-
- Indo-European root: maghu-
- Indo-European root: man-
- Indo-European root: man-