Spectrograph \Spec"tro*graph\, n. [Spectrum + graph.]

(Physics)
   (a) An apparatus for photographing or mapping a spectrum.
   (b) A photograph or picture of a spectrum. -- Spec`tro*graph"ic, a. -- Spec`tro*graph"ic*al*ly, adv. -- Spec*trog"ra*phy, n.

Source: Webster's Revised Unabridged Dictionary (1913)