Lewis & Short

grandĭtas, ātis, f. [grandis], greatness.

  1. * I. Lit., of age (acc. to grandis, I. B.): aetatis granditas, Sisenn. ap. Non. 115, 13.
  2. II. Trop., of style (v. grandis, II. B.), grandeur, sublimity (very rare): idque apparet ex genere et granditate verborum, * Cic. Brut. 31, 121: non illi vis, non granditas, non sublimitas defuit, Plin. Ep. 6, 21, 5.