noun. periapsis in solar orbit; the point in the orbit of a planet or comet where it is nearest to the sun.
- point of periapsis
Example sentences of the word perihelion
1. Noun, singular or mass
The two most important distances between the Earth and sun are described as perihelion, or the point in Earth's orbit when it's closest to the sun, and aphelion, or when its the farthest away.