Source : Webster's Revised Unabridged Dictionary (1913)

Oscillator \Os"cil*la`tor\, n.
   One that oscillates; specif.:
   (a) (Elec.) Any device for producing electric oscillations;
       esp., an apparatus for generating electric waves in a
       system of wireless telegraphy.
   (b) (Mech.) An instrument for measuring rigidity by the
       torsional oscillations of a weighted wire.

Source : WordNet®

oscillator
     n : generator that produces sonic oscillations or alternating
         current