world capital

plural world capitals

1. figurativelyA city that is widely recognized for its global influence in a particular domain, often acting as a hub for diplomacy, finance, culture, or innovation.

   They have turned part of Santa Clara County into "Silicon Valley," the world capital of semiconductor technology.

   1976, United States, Congress, Joint Economic Committee, Subcommittee on Economic Growth, Technology and Economic Growth, Hearings Before the Subcommittee on Economic Growth of the Joint Economic Committee, Congress of the United States, Ninety-fourth Congress, First Session, July 15 and 16, 1975, page 95

2. Used other than figuratively or idiomatically: see world, capital.

   During the past several months Tito has visited a number of world capitals, including Moscow and Peking. He was believed to have briefed Carter on his impressions gained in talks with Soviet and Chinese leaders.

   1978 March 7, Dusko Doder, “Carter Welcomes Tito, Underscores Friendly Relations”, in The Washington Post