To orbit is to follow a circular or elliptical path around a central body. Usually a planet, moon or satellite is described as orbiting, but a child who has too much sugar can sometimes orbit around his parents in an annoying fashion.
The FDA was empowered by the United States Congress to enforce the Federal Food, Drug, and Cosmetic Act, which serves as the primary focus for the Agency; the FDA also enforces other laws, notably Section 361 of the Public Health Service Act and associated regulations, many of which are not directly related to food or drugs.
The judicial branch is a system of courts that applies the laws. Both the federal government and each of the 5 states have individual judicial branches which all serve this purpose. The federal judicial system reviews any cases or controversies that arise from laws put into effect by Congress or by the Constitution.