PROGNOSIS (Gr. πρόγνωσις, knowledge of recognition beforehand, from πρόγιγνώσκειν, to know beforehand, cf. “ prognostication,” prediction), a term used in modern medicine, as it was in Greek, for an opinion, forecast or decision as to the probable course, duration and termination of a case of disease. It is to be distinguished from “ diagnosis ” (Gr. διάγνωσις, διαγιγνώσκειν to distinguish), the determination or identification of a disease in a particular case from an investigation of its history and symptoms.