'arch-negotiator' originates from English as a compound of the prefix 'arch-' and the noun 'negotiator'. 'arch-' ultimately comes from Greek 'arkhi-' meaning 'chief' or 'principal', while 'negotiator' comes from Latin 'negotiator' (agent in business), from 'negotium' meaning 'business' or 'task'.

'negotiator' entered English via Latin 'negotiator' and Old French 'negotiateur' before becoming Middle/Modern English 'negotiator'. The prefix 'arch-' (from Greek 'arkhi-' / Late Latin usage) has long been used in English compounds (e.g. 'arch-enemy') to indicate principal or extreme degree, and was combined with 'negotiator' to form the compound 'arch-negotiator'.

Initially the elements meant 'chief' (arch-) and 'business agent' (negotiator); over time the compound came to be used specifically for the lead representative in negotiations and, informally, for an especially skilled negotiator.