DICT.TW Dictionary Taiwan
Ap·si·des n. pl. See Apsis.
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Ap·sis n.; pl. Apsides See Apse.
1. Astron. 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. In a curve referred to polar coördinates, any point for which the radius vector is a maximum or minimum.
3. Arch. Same as Apse.
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apsis
n : a domed or vaulted recess or projection on a building
especially the east end of a church; usually contains the
altar [syn: apse]
[also: apsides (pl)]