| Noun | 1. | syphilis - a common venereal disease caused by the Treponema pallidum spirochete; symptoms change through progressive stages; can be congenital (transmitted through the placenta)primary syphilis - the first stage; characterized by a chancre at the site of infection secondary syphilis - the second stage; characterized by eruptions of the skin and mucous membrane tertiary syphilis - the third stage; characterized by involvement of internal organs especially the brain and spinal cord as well as the heart and liver chancre - a small hard painless nodule at the site of entry of a pathogen (as syphilis) | |