- 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.
- Architecture. an apse.
Origin of apsis
1595–1605; < Latin < Greek hapsís (felloe of) a wheel, arch, vault, orig., fastening, equivalent to háp(tein) to fasten + -sis -sis
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Examples from the Web for apsis
In 1473, he was employed by the latter to paint, in the apsis of SS.Memoirs of the Dukes of Urbino, Volume II (of 3)
It does not span the apsis of a church; it spans rivers and valleys.
It has an altar and an apsis, but it is adapted to preaching rather than to singing.
The apsis itself is probably a re-erection with the original materials, but anterior to Duke William.The Chronicle of the Norman Conquest
Then a man got up by the apsis and stood there half hidden by the stalactite rock.The German Lieutenant and Other Stories
- 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
- another name for apse (def. 1)
C17: via Latin from Greek; see apse
Word Origin and History for apsis
"perigree of the moon, perihelion of a planet" (plural apsides), 1650s, from Latin apsis "arch, vault" (see apse).
Online Etymology Dictionary, © 2010 Douglas Harper
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.