1. The point of greatest and the point of least distance from the sun the line connecting these is called the line of the apsides; an apse.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• absys,
• abysis,
• apixs,
• zpsis,
• wpsis,
• qpsis,
• aosis,
• alsis,
• a-sis,
• a0sis,
• apais,
• apzis,
• apdis,
• apeis,
• apwis,
• apsus,
• apsjs,
• apsks,
• apsos,
• aps9s

• aphesis,
• aphasic.

The adjective form of "apsis" is "apsidal".

The plural of the "apsis" can be the "apsides".

The singular of the "apsis" can be the "apsis".