The point in an orbit that is farthest from the body being orbited; the highest point of an elliptical orbit.
From Greek 'apo-' (away from) + 'apsis' (a point of orbit). Technical astronomy term for orbital positions.
The Moon's apoapsis is about 252,000 miles from Earth, while its periapsis is 226,000 miles away—the difference gives the Moon's orbit an interesting elongated shape.
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