APSIS

apse, apsis

(noun) a domed or vaulted recess or projection on a building especially the east end of a church; usually contains the altar

Source: WordNet® 3.1

Etymology

Noun

apsis (plural apsides)

(architecture) A recess or projection, with a dome or vault, at the east end of a church; an apse.

(astronomy) Either of the points in the elliptical orbit of a planet or comet where it is closest or furthest from the sun; perihelion or aphelion; an apside

Anagrams

• AISPs, IASPs, aspis

Source: Wiktionary

Ap"sis, n.; pl. Apsides. See Apse. Etym: [L. apsis, absis, Gr.

1. (Astron.)

Definition: One of the two points of an orbit, as of a planet or satellite, which are at the greatest and least distance from the central body, corresponding to the aphelion and perihelion of a planet, or to the apogee and perigee of the moon. The more distant is called the higher apsis; the other, the lower apsis; and the line joining them, the line of apsides.

2. (Math.)

Definition: In a curve referred to polar coördinates, any point for which the radius vector is a maximum or minimum.

3. (Arch.)

Definition: Same as Apse.

Source: Webster’s Unabridged Dictionary 1913 Edition