Lewis & Short

scansĭo, ōnis, f. [scando], a climbing up (very rare).

  1. * I. Lit.: quā simplici scansione scandebant in lectum, Varr. L. L. 5, § 168 Müll.
  2. II. Trop.: sonorum, a rising or elevation of tones of the voice, Vitr. 6, 1.
    In gram., a metrical reading or scanning of verse, scansion, Beda, p. 2368 P.; Diom. 494 sq. P.