'arch-sorcerer' originates from English, combining the prefix 'arch-' (from Greek 'arkhē'/'arkhos' meaning 'chief, principal') and 'sorcerer' (from Old French 'sorcier', ultimately from Latin 'sortiarius' related to 'sors' meaning 'lot, fate').

'arch-' entered English via Latin/Old French and attached to nouns (e.g. 'archbishop'); 'sorcier' in Old French became 'sorcerer' in Middle English; the compound 'arch-sorcerer' was formed in Modern English to denote a chief sorcerer.

Initially it meant 'chief' + 'one who practices magic', but over time it evolved into the current sense of 'the most powerful or senior sorcerer.'