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.

Source: Webster's Revised Unabridged Dictionary (1913)
 

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: Webster's Revised Unabridged Dictionary (1913)