apsis

American  

[ap-sis] / ˈæp sɪs /

noun

• apsides
  plural

1. Astronomy. 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.

2. Architecture. an apse.

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apsis British  

/ ˈæpsɪs /

noun

1. Also called: apse.  either of two points lying at the extremities of an eccentric orbit of a planet, satellite, etc, such as the aphelion and perihelion of a planet or the apogee and perigee of the moon. The line of apsides connects two such points and is the principal axis of the orbit

2. another name for apse

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apsis Scientific  

/ ăp′sĭs /

• apsides
  plural

1. In the path of an orbiting body, either of the two points at which it is closest to or farthest away from the body it is orbiting.

2. See also apoapsis periapsis

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Other Word Forms

Derived Forms

• apsidal
  adjective

Inflected Forms

Nouns

• apsides
  plural

Etymology

Origin of apsis

1595–1605; < Latin < Greek hapsís (felloe of ) a wheel, arch, vault, originally, fastening, equivalent to háp ( tein ) to fasten + -sis -sis

Example Sentences

See Examples For:

apsis apsides

The apsis is terminated by a straight wall.

From The Argosy Vol. 51, No. 4, April, 1891 by Charles W. Wood

It is a curious structure in brick and mortar, with an apsis and an odd arrangement of round arches sunken in the outer wall and still deeper pointed ones.

From Castilian Days by John Hay

On the eastern side of each transept is a small chapel, ending, like the choir, in a semi-circular apsis, which rises no higher than the top of the basement story.

From Account of a Tour in Normandy, Volume 2 by Dawson Turner

Behind us rises the noble apsis of the cathedral.

From The Brotherhood of Consolation by Katharine Prescott Wormeley

They were soon able to distinguish the epochs, and, disdainful of sacristans, they would say: "Ha! a Romanesque apsis!"

From Bouvard and Pécuchet A Tragi-comic Novel of Bourgeois Life by Gustave Flaubert

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

And, we might also ask, why the tangential resistance to the comet of Encke should not also produce a retrograde motion in the apsides of the orbit, instead of diminishing its period?

From Outlines of a Mechanical Theory of Storms Containing the True Law of Lunar Influence by Thomas Bassnett

The more distant is called the higher apsis; the other, the lower apsis; and the line joining them, the line of apsides.

From Webster's Unabridged Dictionary by Noah Webster

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

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