Source : Webster's Revised Unabridged Dictionary (1913)

Fifteen \Fif"teen`\, a. [OE. fiftene, AS. f[=i]ft[=y]ne,
   f[=i]ft[=e]ne. See {Five}, and {Ten}, and cf. {Fifty}.]
   Five and ten; one more than fourteen.

Fifteen \Fif"teen`\, n.
   1. The sum of five and ten; fifteen units or objects.

   2. A symbol representing fifteen units, as 15, or xv.

Source : WordNet®

fifteen
     adj : being one more than fourteen [syn: {15}, {xv}]
     n : the cardinal number that is the sum of fourteen and one
         [syn: {15}, {XV}]