vibrator
    n 1: a mechanical device that vibrates; "a reed is the vibrator
         that produces the sound"
    2: mechanical device that produces vibratory motion; used for
       massage

Vibrator \Vi"bra*tor\, n.
   One that vibrates, or causes vibration or oscillation of any
   kind; specif.
   (a) (Elec.) (1) A trembler, as of an electric bell. (2) A
       vibrating reed for transmitting or receiving pulsating
       currents in a harmonic telegraph system. (3) A device for
       vibrating the pen of a siphon recorder to diminish
       frictional resistance on the paper. (4) An oscillator.
   (b) An ink-distributing roller in a printing machine, having
       an additional vibratory motion.
   (a) (Music) A vibrating reed, esp. in a reed organ.
   (d) (Weaving) Any of various vibrating devices, as one for
       slackening the warp as a shed opens.
   (e) An attachment, usually pneumatic, in a molding machine to
       shake the pattern loose.
   (f) a small electrical device held in the hand, with a motor
       that causes the device and hand to vibrate, and is used
       for vibratory massage.
       [Webster 1913 Suppl. +PJC]