'oligarchal' originates from Greek, specifically the word 'oligarchēs', where 'oligos' meant 'few' and 'arkhein' meant 'to rule'.

'oligarchal' changed from the Greek term 'oligarchēs' (used to denote 'rule by a few'), passed into Late Latin/Medieval Latin forms and the noun 'oligarch' in English, and eventually formed the Modern English adjective 'oligarchal' (and variant 'oligarchical').

Initially it referred directly to the concept or rulers of 'rule by a few'; over time it evolved into an adjective describing systems, structures, policies, or tendencies that embody or favor that form of rule.