'avocatory' originates from Latin, specifically the word 'avocare', where 'a-' (from 'ab-'/'ad-') meant 'away' or 'from' and 'vocare' meant 'to call'.

'avocatory' derived via Medieval Latin (e.g. 'avocatorius') and later Low Latin uses meaning 'calling away'; it entered English in a learned form as 'avocatory' with the adjectival suffix -ory.

Initially it referred literally to the action 'to call away' or the act of removing; over time it developed the adjectival sense 'tending to call away' (i.e., diverting) and a specialized legal sense relating to transfer of jurisdiction.