The perihelion is the point in the orbit of a planet, minor planet, or comet, where it is nearest to the Sun. It is the opposite of aphelion, which is the point in the orbit where the celestial body is farthest from its Sun.

The word "perihelion" stems from the Ancient Greek words "peri", meaning "near", and "helios", meaning "the Sun". "Aphelion" derives from the preposition "apo", meaning "away, off, apart". (The similar words "perigee" and "apogee" refer to the nearest and furthest points in some object's orbit around a planet.)

According to Kepler's first law of planetary motion, all planets, comets, and asteroids in the Solar System have approximately elliptical orbits around the Sun. (Any single revolution of a body around its parent object is only approximately elliptical, because precession of the perihelion prevents the orbit from being a simple closed curve such as an ellipse.) Hence, an orbiting body has a closest and a farthest point from its parent object, that is, a perihelion and an aphelion, known collectively as apsides. Orbital eccentricity measures the flatness (departure from a perfect circle) of the orbit.

Perihelion is the point of closest approach to the Sun of a body orbiting the Sun.

Perihelion may also refer to:

Perihelion: The Prophecy is an RPG developed by Morbid Visions and published by Psygnosis in 1993 for Amiga computer. The player controls six characters which are supposed to save the realm they live in from an evil being which is slowly materialising into their dimension. The character races are rather unique in RPGs and include Bionecrons, Symbions and various cross-breeds between humans, animals and mechanical entities.

The gameplay concerns juggling through the set of screens which are responsible for different parts of the game, such as exploring the dungeon and a world map, inventory management, spell creation (very sophisticated runic system), network connections (used also for conversation purposes) and battle mode (a bit archaic, turn-based system). Everything is controlled from a set of icons.

The game has 16-bit graphics which are mostly in grey and orange shades. The sound and music are conducted with attention to details, and the music changes depending on the action on the screen.