Definition of fifteen:

• Five and ten.

Usage examples for fifteen

1. " It is fifteen thousand pounds, is it not?  Blind Love by Wilkie Collins

2. We've been together since we were fifteen- high school.  Michelangelo's Shoulder by John Moncure Wetterau

3. Well, I suppose an old body like myself mustn't expect to be company for a girl of fifteen!  The Luckiest Girl in the School by Angela Brazil

4. It is well to lie down, or sit quietly and read, fifteen minutes before eating, and directly afterwards, if possible.  A Practical Physiology by Albert F. Blaisdell