'apsis-related' originates from Modern English, combining the noun 'apsis' (itself from Greek 'hapsis' via Latin 'apsis') and the English suffix '-related'.

'apsis' changed from Greek 'hapsis' to Latin 'apsis' and entered scientific English as 'apsis'; 'apsis-related' was formed in Modern English by compounding 'apsis' with '-related' to mean 'related to an apsis'.

Initially, 'apsis' meant 'arch' or 'loop' in Greek, but over time it was specialized in astronomy to mean 'a point of greatest or least distance in an orbit'; accordingly, 'apsis-related' now means 'related to an orbital extreme point'.