Words of the day: perihelion and aphelion
These two words refer to two points in the orbit of the Earth around the Sun.
Although the orbit is close to being a circle (like the shape of a ball), it is not quite circular; it is instead an ellipse (like the shape of an egg).
The point at which the Earth is nearest to the sun is called the perihelion and the point at which the Earth is furthest from the Sun is known as the aphelion. The word ‘helion’ comes the name of the Greek sun god Helios, while ‘peri’ is Greek for near and ‘apo’ is Greek for far.
This information is in the book I am currently reading: “The Magic Of Reality” by Richard Dawkins.