Vibrion may also refer to: the singular form of vibrio, a genus of anaerobic bacteria with a comma-like shape. Vibrion is an antiquated term for microorganisms, especially pathogenic ones; see Germ theory of disease. The term was specifically used in reference to motile microorganisms, and the name of the genus Vibrio derives from this term. The term is closely tied to the history of the study of cholera. It was used in biological literature between the late 19th century and the 1920s.