- a chronic infectious disease, caused by a spirochete, Treponema pallidum, usually venereal in origin but often congenital, and affecting almost any organ or tissue in the body, especially the genitals, skin, mucous membranes, aorta, brain, liver, bones, and nerves.
- a venereal disease caused by infection with the microorganism Treponema pallidum: characterized by an ulcerating chancre, usually on the genitals and progressing through the lymphatic system to nearly all tissues of the body, producing serious clinical manifestations
