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
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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.
They are called the lower or nearer, and the higher or more distant apsides respectively.
From Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 3 "Apollodorus" to "Aral" by Various
That is to say, he assumed a revolving line of apsides in an elliptical orbit traversed by a pretty strongly compressed pair of globes.
From A Popular History of Astronomy During the Nineteenth Century Fourth Edition by Agnes M. (Agnes Mary) Clerke
The line of the apsides has a slow forward angular motion in the plane of the planet's orbit, being retrograde only in the case of Venus.
From The New Gresham Encyclopedia. Vol. 1 Part 2 Amiel to Atrauli 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
From the north and south faces of both rooms are semi-circular apsides, projecting 6 feet 6 inches, containing the Collimator piers and the vertical openings for observation.
From The Uses of Astronomy An Oration Delivered at Albany on the 28th of July, 1856 by Edward Everett
