The highest point.
The point, in any trajectory of an object in space, where it is farthest from the Earth.
The point, in an orbit about the Earth, that is farthest from the Earth: the apoapsis of an Earth orbiter.
The point, in an orbit about any planet, that is farthest from the planet: the apoapsis of any satellite.
The most extreme or furthest point of something.
A hand or foot.
A limb (“major appendage of a human or animal such as an arm, leg, or wing”).
An extreme measure.