'annullate' originates from Latin, specifically the verb 'annullare', where 'ad-' (expressed in form 'an-') meant 'to' or 'toward' and 'nullus' meant 'not any' or 'nothing'.

'annullare' passed into Medieval Latin and then through Old French/Anglo-Norman influences as forms like 'anuler'/'anueler', eventually appearing in English as the learned verb 'annullate' alongside the simpler 'annul'.

Initially, the Latin root carried the idea of making 'nothing' of something (to reduce to nothing); over time it evolved into the legal/formal sense 'to make void' or 'cancel', which is its current usage.