nounpl. -·li·ons or -·lia
the point farthest from the sun in the orbit of a planet or comet, or of a man-made satellite in orbit around the sun
Origin of aphelionModL, altered (as if Gr) by Johannes Kepler from earlier aphelium from Classical Greek apo-, from + h?lios, sun; modeled on Classical Latin apogaeum, apogee
The point on the orbit of a celestial body that is farthest from the sun.
Origin of aphelionFrom New Latin aphēlium Greek apo- apo- Greek hēlios sun ; see sāwel- in Indo-European roots.