Source : Webster's Revised Unabridged Dictionary (1913)

Galvanometer \Gal`va*nom"e*ter\, n. [Galvanic + -meter: cf. F.
   galvanom[`e]tre.] (Elec.)
   An instrument or apparatus for measuring the intensity of an
   electric current, usually by the deflection of a magnetic
   needle.

   {Differential galvanometer}. See under {Differental}, a.

   {Sine galvanometer}, {Cosine galvanometer}, {Tangent
   galvanometer} (Elec.), a galvanometer in which the sine,
      cosine, or tangent respectively, of the angle through
      which the needle is deflected, is proportional to the
      strength of the current passed through the instrument.

Source : WordNet®

galvanometer
     n : meter for detecting or comparing or measuring small electric
         currents