The Collaborative International Dictionary of English v.0.48:

Oscillatory \Os"cil*la*to*ry\, a. [Cf. F. oscillatoire. See
   Oscillate.]
   Moving, or characterized by motion, backward and forward like
   a pendulum; swinging; oscillating; vibratory; as, oscillatory
   motion.
   [1913 Webster]

WordNet (r) 3.0 (2006):

oscillatory
    adj 1: having periodic vibrations [syn: oscillatory,
           oscillating]