Entry 1 sense Webster, 1913 microphonous /(mī̇*krŏf"ō̇*nŭs or mĭ*krŏf"ō̇*nŭs)/ · mi·croph·o·nous · IPA /maɪ̯ˈkrɒ.fə.nəs/ 01 a. Serving to augment the intensity of weak sounds; microcoustic. 1. Serving to augment the intensity of weak sounds; microcoustic.