
(from the article `apse`) ...orbit that are nearest to, and farthest from, the focus, or centre of attraction. The line of apsides, connecting the two points, is the major ...
Found on
http://www.britannica.com/eb/a-z/p/44

The point on a spacecrafts orbit at which it is nearest to the centre of mass of the system. See also: Periapsis, Perigee.
Found on
https://www.encyclo.co.uk/local/20687
No exact match found.