passus

from The Collaborative International Dictionary of English v.0.48

Passus \Pas"sus\, n.; pl. L. {Passus}, E. {Passuses}. [L., a
   step, a pace. See {Pace}.]
   A division or part; a canto; as, the passus of Piers Plowman.
   See 2d {Fit}.
   [1913 Webster]