'pacific' originates from Latin, specifically the word 'pacificus', where 'pax' meant 'peace' and 'facere' (or the -fic element) meant 'to make' or 'making'.

'pacificus' passed into Old French as 'pacifique' and then into Middle English (as 'pacific' / 'pacifique'), eventually becoming the modern English 'pacific'.

Initially it meant 'making peace' or 'bringing about peace'; over time it broadened to describe something 'peaceful' or 'calm' rather than only the active sense of 'making peace'.