Source : Webster's Revised Unabridged Dictionary (1913)

Magnetometer \Mag`net*om"e*ter\, n. [Magneto- + -meter: cf. F.
   magn['e]tom[`e]tre.] (Physics)
   An instrument for measuring the intensity of magnetic forces;
   also, less frequently, an instrument for determining any of
   the terrestrial magnetic elements, as the dip and
   declination.

Source : WordNet®

magnetometer
     n : a meter to compare strengths of magnetic fields [syn: {gaussmeter}]