"Periapsis" or "Periastron"? I was taught from Bate Mueller and White, that the proper terms for the closest and furthest points and distances from a body in orbit around another unspecified body are &quot;periapsis&quot; and &quot;apoapsis&quot; as depicted here.

However, in comments to this question, it is strongly suggested that the usage of these terms is incorrect.

“Apses” are the points closest to and furthest from a primary body—see
en.wikipedia.org/wiki/Apsis, among many other sources. These points
are called “peri-” and “apo-” with the suffix pertaining to the body
(e.g. “-gee” for Earth, thus “perigee”). The generic word for a
celestial body is ἄστρον


“Periapsis” would mean “the point closest to the point closest to the
body.” Nonsense. The proper word is “periastron”: “periapse” is a
misconstruction.

Is the usage of &quot;periapsis&quot; really incorrect or perhaps just a misnomer?
Should we replace &quot;periapsis&quot; with &quot;periastron&quot;?
No. These words are English, not Greek.  &quot;Periapsis&quot; means the point on the orbit when the two bodies are at their closest.  It doesn't matter if this good Greek or bad Greek, it is correct English.
Apsis actually derives from &quot;arch&quot; and indicates the two points where the orbital curve is most &quot;arched&quot;: ie the points of greatest curvature.  There is the &quot;periapsis&quot;: The close point of greatest curvature and the &quot;apoapsis&quot; &quot;the distant point of great curvature&quot;.
There is no such thing as a &quot;misconstruction&quot;.  The idea that a word does not mean what it means is obviously nonsensical