Webster’s Revised Unabridged Dictionary · 1913
Forty
For′ty (fôr′ty̆), a. [OE. forti, fourti, fowerti, AS. feówertig; feówer four + suff. -tig ten; akin to OS. fiwartig, fiartig, D. veertig, G. vierzig, Icel. fjörutīu, Sw. fyratio, Dan. fyrretyve, Goth. fidwōr tigjus. See Four, and Ten, and cf. Fourteen.] Four times ten; thirty-nine and one more.
For′ty, n.; pl. Forties (-tĭz). 1. The sum of four tens; forty units or objects.
2. A symbol expressing forty units; as, 40, or xl.