apsis
noun
either of two points in an eccentric orbit, one higher apsis farthest from the center of attraction, the other lower apsis nearest to the center of attraction.
apsides
-
pluralof apsis.plural
The grammatical form denoting more than one person, place, thing, or idea.
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
The time of revolution of a primary or secondary planet in reference to its line of apsides; that is, from one perigee or apogee to another.
From The Sailor's Word-Book An Alphabetical Digest of Nautical Terms, including Some More Especially Military and Scientific, but Useful to Seamen; as well as Archaisms of Early Voyagers, etc. by Sir Edward Belcher
Of or pertaining to the apsides of an orbit.
From Webster's Unabridged Dictionary by Noah Webster
The two are joined by a diameter called the line of the apsides.
From The Sailor's Word-Book An Alphabetical Digest of Nautical Terms, including Some More Especially Military and Scientific, but Useful to Seamen; as well as Archaisms of Early Voyagers, etc. by Sir Edward Belcher
The phenomenon of the progression of the apsides of an oval orbit, which is here alluded to, is familiar to all students in mechanics.
From The International Monthly, Volume 3, No. 3, June, 1851 by Various
Apsis, plural apsides, the line joining the aphelion and perihelion points; or the major axis of elliptical orbits.
From Recreations in Astronomy With Directions for Practical Experiments and Telescopic Work by Henry White Warren
