'back-related' originates as a compound of the English word 'back' (from Old English 'bæc') and the adjective 'related' (from Latin via Old French, ultimately from Latin 'relatus'). 'bæc' meant 'the rear or rear part', and 'relatus' is the past participle of 'referre'.

'back' comes from Old English 'bæc' and 'related' comes from Latin 'relatus' through Old French and Middle English; the modern compound 'back-related' developed in Contemporary English by joining these two elements to describe things pertaining to the back.

The components originally meant 'rear' (for 'back') and 'carried back / told' (for the root of 'related'); combined as a compound the meaning has developed straightforwardly into 'relating to the back' and has remained literal in modern usage.