Source : Webster's Revised Unabridged Dictionary (1913)

Spectrometer \Spec*trom"e*ter\, n. [Spectrum + -meter.]
   (Physics)
   A spectroscope fitted for measurements of the luminious
   spectra observed with it.

Source : WordNet®

spectrometer
     n : spectroscope for obtaining a mass spectrum by deflecting
         ions into a thin slit and measuring the ion current with
         an electrometer [syn: {mass spectrometer}]