Source : Webster's Revised Unabridged Dictionary (1913)

Pedesis \Pe*de"sis\, n. [NL., from Gr. ? a leaping.]
   Same as {Brownian movement}, under {Brownian}.

Source : WordNet®

pedesis
     n : the random motion of small particles suspended in a gas or
         liquid [syn: {Brownian movement}, {Brownian motion}]