Meaning

• The point, in an orbit about the Earth, that is furthest from the Earth: the apoapsis of an Earth orbiter.

• (more generally) The point, in an orbit about any planet, that is farthest from the planet: the apoapsis of any satellite.

• (possibly obsolete outside astrology) The point, in any trajectory of an object in space, where it is furthest from the Earth.

• The highest point.