Gonorrhea: A bacterial infection that is transmitted by sexual contact. Gonorrhea is one of the oldest known sexually transmitted diseases (STDs), and it is caused by the Neisseria gonorrhoeae bacteria. Men with gonorrhea may have a yellowish discharge from the penis accompanied by itching and burning. More than half of women with gonorrhea do not have any symptoms. If symptoms occur, they may include burning or frequent urination, yellowish vaginal discharge, redness and swelling of the genitals, and a burning or itching of the vaginal area. If untreated, gonorrhea can lead to severe pelvic infections and even sterility. Complications in later life can include inflammation of the heart valves, arthritis, and eye infections. Gonorrhea can also cause eye infections in babies born of infected mothers. Gonorrhea is treated with antibiotics.