The Collaborative International Dictionary of English v.0.48:

Peristalsis \Per`i*stal"sis\, n. [NL. See Peristaltic.]
   (Physiol.)
   Peristaltic contraction or action.
   [1913 Webster]

WordNet (r) 3.0 (2006):

peristalsis
    n 1: the process of wavelike muscle contractions of the
         alimentary tract that moves food along [syn: peristalsis,
         vermiculation] [ant: anastalsis]