'arbitrational' originates from Latin, specifically the word 'arbitratio', where 'arbiter' meant 'judge' and the suffix '-ation' indicated 'action or process'; the English adjective was formed by adding the suffix '-al' to 'arbitration'.

'arbitrational' changed from Middle English 'arbitracion' (borrowed via Old French 'arbitracion' from Latin 'arbitratio') and eventually became the modern English adjective 'arbitrational' by suffixation ('-al').

Initially it referred to the act or process of judgment or decision ('arbitration'); over time the derivative adjective came to mean 'relating to arbitration' as used in legal and dispute-resolution contexts.