Lewis & Short

quīnī-dēni or quin-dēni, ae, a, num. distr. adj.

  1. I. Fifteen each: quina dena jugera agri data in singulos pedites sunt, Liv. 35, 40: quini deni pedes, Quint. 1, 10, 43: quindeni pedes, Vitr. 6, 9: anni, Plin. 10, 63, 83, § 178: HS., Suet. Claud. 10: menses, Curt. 8, 9, 35.
  2. II. In gen., fifteen: quindenis hastis corpus transfigi, Plaut. Most. 2, 1, 11.