Lewis & Short

longĭtūdo, ĭnis, f. [longus], length.

  1. I. Lit.: in hac immensitate latitudinum, longitudinum, altitudinum, Cic. N. D. 1, 20, 54: itineris, id. Phil. 9, 1, 2: pontis, Caes. B. G. 6, 29: longitudines et brevitates in sonis, Cic. Or. 51, 173: diffindere aliquid in longitudinem, lengthwise, id. Univ. 7: in longitudinem murum praeduxerant, Caes. B. G. 7, 46: longitudinis pedes, Quint. 1, 10, 42; 11, 3, 118; Plin. 16, 34, 62, § 150: Hispania ulterior in duas per longitudinem provincias dividitur, id. 3, 1, 2, § 6.
  2. II. Transf., of time, length, long duration (rare; cf.: longinquitas, diuturnitas): noctis, Cic. Verr. 2, 5, 10, § 26: orationis, id. Part. 17, 59; cf. prooemii, Quint. 4, 1, 62: consulere in longitudinem, to look far ahead, take thought for the future, Ter. Heaut. 5, 2, 10.