apsis

n. ஞாயிற்றின் நெடுஞ்சேய்மையில் அல்லது மிக அண்மையில் அமைந்த கிரகத்தின் இடம், திங்கள் நிலவுலகுக்கு நெடுஞ்சேய்மையாக அல்லது மிக அண்மையாக இருக்கும் நிலை.

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Ap"sis, n.; pl. Apsides. See Apse. Etym: [L. apsis, absis, Gr. 1. (Astron.) Defn: 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.) Defn: In a curve referred to polar coördinates, any point for which the radius vector is a maximum or minimum. 3. (Arch.) Defn: Same as Apse.

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