epidemiologist|ɛpɪˌdiːmɪˈɒlədʒɪst| [f. next + -ist.] One who studies epidemic diseases. 1880J. Fayrer in Nature XXI. 230 The most important..information to the epidemiologist.1883Fortn.Rev. 1 Aug. 181 An outbreak which epidemiologists have always been unable to explain.