'aphelian' originates from New Latin/Scientific Latin, specifically from the word 'aphelion', which itself comes from Greek elements 'apo-' meaning 'away from' and 'hēlios' meaning 'sun'.

'aphelion' came into scientific use via Latin from the Greek phrase formed from 'apo-' + 'hēlios'; the English adjective 'aphelian' was later formed from 'aphelion' with the adjectival suffix '-ian'.

Initially the root referred to the point in an orbit farthest from the sun ('aphelion'); over time the adjective 'aphelian' came to mean 'pertaining to or located at that point' and is used to describe positions or conditions at aphelion.