der·mat·o·graph \(ˌ)dərˈmad.əˌgraf, ˈdərməd.ə-\noun Etymology:dermat- + -graph : an instrument for producing markings on the skin: as a.: a crayon used by surgeons to outline internal organs on the body surface < sketch the outline of the liver with a dermatograph on the abdominal skin > b.: a crayon used to test for allergies