'aristomonarchy' originates from a modern English coinage combining Greek elements: 'aristo-' from Greek 'aristos' meaning 'best' (used to denote the aristocracy) and 'monarchy' from Greek 'monarkhia' meaning 'single rule' or 'rule by one'.

'aristomonarchy' is a compound formed in Modern English by blending 'aristo-' (aristocracy) with 'monarchy'; it did not pass through a long medieval English form but follows the pattern of other 19th–20th century scholarly coinages combining Greek roots.

As a neologism it originally described theoretical or comparative forms of government combining aristocratic and monarchical elements; its usage has come to denote both deliberate mixed systems and cases where aristocratic power effectively dominates under a monarchy.