noun. 
                    The point, in an orbit about the Earth, that is furthest from the Earth: the apoapsis of an Earth orbiter.
                  
                
                  
                    noun. 
                    The point, in an orbit about any planet, that is farthest from the planet: the apoapsis of any satellite.
                  
                
                  
                    noun. 
                    The point, in any trajectory of an object in space, where it is furthest from the Earth.
                  
                
                  
                    noun. 
                    The highest point.