Entry 3 senses · 2 variants Webster, 1913 Fifteen /fĭf'tēn/ · Fif·teen · IPA /ˈfɪf.tiːn/ a. n. 01 a. Five and ten; one more than fourteen. 1. Five and ten; one more than fourteen. 02 n. The sum of five and ten; fifteen units or objects. 1. The sum of five and ten; fifteen units or objects. 2. A symbol representing fifteen units, as 15, or xv.