'apoapsis' originates from Greek elements: the prefix 'apo-' from Greek 'ἀπό' meaning 'away from' and 'apsis' from Greek 'ἁψίς' meaning 'arch' or 'loop' (used in astronomy to denote an orbital extremity).

'apsis' comes from Greek 'ἁψίς' and entered scientific/astronomical Latin and then English as 'apsis'; the compound 'apo-' + 'apsis' was formed in modern astronomical terminology to denote the farthest point in an orbit, resulting in 'apoapsis'.

Initially derived from words meaning 'away' and 'arch/loop', it came to be used specifically in astronomy to mean 'the point in an orbit farthest from the central body' (its current technical sense).