duopoly

1. (economics) An economic condition in which two sellers exert most control over the market of a commodity.Examples: "Modern examples of duopoly include the American markets for credit cards (Visa and MasterCard), smartphones (Apple and Google), soft drinks (Coca-Cola and Pepsi), and airplanes (Airbus and Boeing)."countableuncountable

2. (by extension)Examples: "In 2011, his spirit and body were shattered by Jo-Wilfried Tsonga in the semi-finals. Last night, the stakes were just as high – even though the tournament is not out of the first week – because there is a creeping perception that the [Roger] Federer–[Rafael] Nadal duopoly is slowly giving way under pressure from below."; "In Spain, Socialist and PP governments have alternated since the 1980s. This cosy duopoly was weakened by the long recession that followed the bursting of Spain’s housing bubble in 2007."; "And these industrial farms have concentrated into a series of duopolies. Google and Apple’s browsers have nearly 85% of the world market share. Microsoft and Apple’s two desktop operating systems have almost 90%. Google runs about 90% of global search. More than half of all phones come from Apple and Samsung, while 99% of mobile operating systems are from Google or Apple. Apple and Google’s email clients manage nearly 90% of global email. GoDaddy and Cloudflare serve about 50% of global domain name system requests. And so on."broadlycountableuncountable

3. (by extension)Synonyms: twinstickbroadlycountableuncountable