'ratify' originates from Late Latin, specifically the word 'ratificare', where 'rati-' (from 'ratus') meant 'calculated, fixed' and '-ficare' (from 'facere') meant 'to make'.

'ratify' changed from Late Latin 'ratificare' to Old French 'ratifier' and then entered Middle English as 'ratifien', eventually becoming the modern English word 'ratify'.

Initially, it meant 'to make firm or establish'; over time it evolved into its current meaning of 'to confirm or give formal consent (often to treaties or agreements)'.