What does duopoly mean?
A duopoly is a market structure in which two firms together dominate the supply of a good or service, leaving little meaningful room for competitors. The term comes from economics, where it sits between monopoly (one seller) and oligopoly (a few sellers) as a specific case of concentrated market power. Duopolies can arise naturally through economies of scale or be entrenched by regulation and high barriers to entry, and they are often scrutinised by antitrust authorities because prices and choices may suffer when only two players remain. Beyond commerce, duopoly is applied figuratively to politics — most famously to describe two-party systems — and to media, technology platforms, and other fields where a pair of incumbents controls access. The word carries a slightly critical connotation, suggesting cosy dominance rather than healthy rivalry, which makes it a favourite of commentators arguing for reform or competition.
A market condition in which two companies are the only, or overwhelmingly dominant, suppliers of a particular product or service.
"The aircraft-manufacturing industry has long been described as a duopoly."
Often used with modifiers such as 'effective', 'virtual', or 'near-duopoly' when two firms dominate without being the literal only suppliers.
More broadly, any situation in which two parties or entities jointly exercise exclusive control over an activity or domain.
"Voters frustrated with the political duopoly increasingly support independent candidates."
Regular plural; used when discussing multiple markets or domains each characterised by a two-firm dominance.
"Economists have studied duopolies ranging from cola manufacturers to credit-card networks."
Swap just the first syllable of 'monopoly' for the Greek word for 'two', and you get the term economists reach for when two giants quietly run an entire industry.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of duopoly
The word duopoly was formed from the Greek prefix 'duo-', meaning 'two', combined with '-poly', from Greek 'pōlein', meaning 'to sell'. It was coined on the model of the older word 'monopoly' (from 'mono-', 'one'), entering English usage in economic writing in the late nineteenth century alongside related coinages such as 'oligopoly'. Its components are entirely Greek, though the compound itself was assembled within modern English economic vocabulary.
How duopoly is actually used
Duopoly is primarily a term of economics and business analysis, with a neutral-to-slightly-critical register: writers often use it to imply that competition has been squeezed out. It appears frequently in journalism about tech platforms, airlines, and political systems. The plural 'duopolies' is regular but uncommon.
Easily confused with duopoly
A monopoly is a market dominated by a single seller, whereas a duopoly is one shared by exactly two.
A duopsony involves only two buyers controlling demand, while a duopoly involves two sellers supplying a market.