apsis

• ⇰ 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 cal
• ⇰ In a curve referred to polar coördinates, any point for which the radius vector is a maximum or minimum.
• ⇰ Same as Apse>.