aphelium means synonym of aphelion. Lexicurio rates it Sui generis — a strength score of 100 out of 100.
Etymology
Unadapted borrowing from Latin aphelium.
noun
- Synonym of aphelion.“Wherefore a Planet, whoſe Orbit is an Ellipſe, having the Sun for a Focus, muſt neceſſarily be urged, even in its aſcent from the Sun, from the Perihelium to the Aphelium, by a Force tending to the Sun, fince an Ellipſe is concave towards both Foci.”