The suffix in the term peritoneal is eal, which means pertaining to.
In this instance, 'peritoneal' means pertaining to the peritoneum (the membrane that lines the abdominal cavity). The suffix "eal" is added to the end of medical terms to modify their meaning. Some other examples include: esophageal (pertaining to the esophagus), tracheal (pertaining to the trachea) and corneal (referring to the cornea).
