periapsis

periapsis  (pr-pss)

Plural periapsides (pr-ps-dz)

The point at which an orbiting object is closest to the body it is orbiting. This point is sometimes given a name that is specific to the body being orbited. For example, the periapsis of an object orbiting Earth is its perigee (from gaia, the Greek word for Earth), and the periapsis of an object orbiting the Sun is its perihelion (from hlios, the Greek word for Sun). According to Kepler's laws of planetary motion, an object is at its greatest velocity at the periapsis. Compare apoapsis.

Thesaurus

Noun

1.

periapsis - (astronomy) the point in an orbit closest to the body being orbited point of periapsis astronomy, uranology - the branch of physics that studies celestial bodies and the universe as a whole celestial point - a point in the heavens (on the celestial sphere) celestial orbit, orbit - the (usually elliptical) path described by one celestial body in its revolution about another; "he plotted the orbit of the moon" perigee - periapsis in Earth orbit; the point in its orbit where a satellite is nearest to the Earth perihelion - periapsis in solar orbit; the point in the orbit of a planet or comet where it is nearest to the sun perijove - periapsis in orbit around Jupiter perilune, periselene - periapsis in orbit around the moon apoapsis, point of apoapsis - (astronomy) the point in an orbit farthest from the body being orbited