Definition of: phonautograph

(fō·nô′tə·graf, -gräf) noun
1. An apparatus designed to record the vibrations of sounds. It was the forerunner of Edison's phonograph.
2. A writing or tracing produced by the mechanical use of sound vibrations. Also pho·nau′to·gram. [<Gk. phōnē sound + autos self + -GRAPH]
—pho·nau′to·graph′ic or ·i·cal adjective
—pho·nau′to·graph′i·cal·ly adverb