- that point in the elliptical orbit of the moon, a planet, etc. nearest to (lower apsis), or that farthest from (higher apsis), the gravitational focus point
- apse (sense )
Origin of apsisL, an arch ; from Classical Greek hapsis, a fastening ; from haptein: see apt
line of apsides
a line joining the lower and higher apsides, forming the major axis of the orbit
- Architecture An apse.
- Astronomy The point of greatest or least distance of the orbit of a celestial body from the center of mass of the system.
Origin of apsisLate Latin, from Latin, arch, vault, from Greek hapsis, from haptein, to fasten.