Source : Webster's Revised Unabridged Dictionary (1913)

Proceleusmatic \Proc`e*leus*mat"ic\, a. [L. proceleusmaticus,
   Gr. ?, fr. ? to rouse to action beforehand; ? + ? to incite;
   cf. F. proc['e]leusmatique.]
   1. Inciting; animating; encouraging. [R.] --Johnson.

   2. (Pros.) Consisting of four short syllables; composed of
      feet of four short syllables each.

Proceleusmatic \Proc`e*leus*mat"ic\, n. (Pros.)
   A foot consisting of four short syllables.