Esophageal cancer describes the disease where cells that line the esophagus change or mutate and become malignant. These cells grow out of control and form a mass or tumor. There are two main types of esophageal cancer:
Trajectory. A trajectory is the path that a moving object follows through space as a function of time. The object might be a projectile or a satellite, for example. It thus includes the meaning of orbitâthe path of a planet, an asteroid or a comet as it travels around a central mass.
orbit definition. In astronomy, the path followed by an object revolving around another object, under the influence of gravitation (see satellite). In physics, the path followed by an electron within an atom. The planets follow elliptical orbits around the sun (see ellipse).