'entreaty' originates from Middle English, specifically the word 'entreaten', where the prefix 'en-' meant 'in/into' and the element 'treat' (from Old French 'traiter' / 'entreter') meant 'to handle, to negotiate'.

'entreaty' changed from Middle English 'entreaten' (and related Old French forms like 'entreter') and eventually became the modern English noun 'entreaty' (with the plural 'entreaties').

Initially it was related to 'treating' or 'negotiating' (handling matters between people), but over time it evolved into its current sense of an 'earnest request' or 'plea'.