spec·trom·e·ter / spekˈträmitər/ • n. an apparatus used for recording and measuring spectra, esp. as a method of analysis.DERIVATIVES: spec·tro·met·ric / ˌspektrəˈmetrik/ adj.spec·trom·e·try / spekˈträmətrē/ n.

spectrometer An instrument which, with associated equipment, furnishes the ratio, or some function of a ratio, of the radiant power of two electromagnetic beams as a function of their spectral wavelength. It requires a source of radiation (in emission spectrometers the sample serves as its own source), a means of distinguishing between different radiation frequencies, and includes narrow band filters, a prism, a diffraction grating, a system of slits to isolate a narrow band of radiation, a samplecontaining system, and a photodetector, amplifier, and output device (meter, recorder, VDU, etc.) See GAMMA-RAY SPECTROMETRY; and MASS SPECTROMETRY.