Wikipedia:

A global city, also called world city or sometimes alpha city or world center, is a city generally considered to be an important node in the global economic system. The concept comes from geography and urban studies, and the idea that globalization can be understood as largely created, facilitated, and enacted in strategic geographic locales according to a hierarchy of importance to the operation of the global system of finance and trade.

The 2004 rankings acknowledged several new indicators while continuing to rank city economics more heavily than political or cultural factors. The 2008 roster, similar to the 1998 version, is sorted into categories of "Alpha" world cities (with four sub-categories), "Beta" world cities (three sub-categories), "Gamma" world cities (three sub-categories) and additional cities with "High sufficiency" or "Sufficiency" presence. The following is a list of the cities in the 2016 rankings, as they appear on the GaWC website:[15]

Alpha ++ cities are cities most integrated with the global economy: London, New York City

Alpha + cities are advanced service niches for the global economy: Singapore, Hong Kong, Paris, Beijing, Tokyo, Dubai, Shanghai

Alpha level cities (sorted in to Alpha cities and Alpha − cities) are cities that link major economic regions into the world economy:

Alpha cities: Sydney, São Paulo, Milan, Chicago, Mexico City, Mumbai, Moscow, Frankfurt, Madrid, Warsaw, Johannesburg, Toronto, Seoul, Istanbul, Kuala Lumpur, Jakarta, Amsterdam, Brussels, Los Angeles

Alpha − cities: Dublin, Melbourne, Washington, New Delhi, Bangkok, Zurich, Vienna, Taipei, Buenos Aires, Stockholm, San Francisco, Guangzhou, Manila, Bogotá, Miami, Luxembourg, Riyadh, Santiago, Barcelona, Tel Aviv, Lisbon

Beta level cities are cities that link moderate economic regions into the world economy and are classified into three sections, Beta + cities, Beta cities, and Beta − cities:

Beta + cities: Prague, Ho Chi Minh City, Boston, Copenhagen, Düsseldorf, Athens, Munich, Atlanta, Bucharest, Helsinki, Budapest, Kiev, Hamburg, Bangalore, Rome, Oslo, Dallas, Cairo, Houston, Lima, Lagos, Caracas, Auckland, Cape Town

Beta cities: Doha, Karachi, Nicosia, Geneva, Montevideo, Berlin, Montreal, Abu Dhabi, Casablanca, Philadelphia, Vancouver, Shenzhen, Sofia, Perth, Hanoi, Beirut, Brisbane, Bratislava, Manama

Beta − cities: Port Louis, Minneapolis, Chennai, Stuttgart, Santo Domingo, Rio de Janeiro, Kuwait City, Chengdu, Panama City, Denver, Lahore, Jeddah, Tunis, Quito, Belgrade, Seattle, Manchester, Guatemala City, Lyon, San José, Tianjin, Calgary, Amman, San Juan, San Salvador, Antwerp, Zagreb, Kolkata, Tallinn, St. Louis, Monterrey, Hyderabad, Edinburgh, San Diego, Cologne, Rotterdam, Dhaka, Islamabad

Gamma level cities are cities that link smaller economic regions into the world economy, and are sorted into three sections, Gamma + cities, Gamma cities, and Gamma − cities:

Gamma + cities: Guayaquil, Cleveland, Riga, Baku, Adelaide, Vilnius, Birmingham, Glasgow, Nanjing, Hangzhou, Colombo, Porto, Qingdao, Valencia, Detroit, Muscat, Osaka, Ljubljana, Kampala, George Town, Managua, Durban, San Jose, Saint Petersburg

Gamma cities: Phoenix, Tegucigalpa, Austin, Pune, Guadalajara, Dalian, Tbilisi, Dar es Salaam, Chongqing, Ankara, Lusaka, Ahmedabad, Cincinnati, Asunción, Harare, Gothenburg, Xiamen, Mosul, Kansas City, Accra, Minsk, Tampa, Turin, Luanda, Abidjan, Tirana, Lausanne, Leeds

Gamma − cities: Taichung, Charlotte, Baltimore, Raleigh, Belfast, Leipzig, Medellín, Wuhan, Douala, Maputo, Skopje, Gaborone, Bristol, Orlando, Dakar, Suzhou, Malmö, Edmonton, Changsha, Strasbourg, Bilbao, Bologna, Columbus, Wellington, Nuremberg, Yangon, Xi'an, Wrocław, Marseille, Dresden, Shenyang, Pittsburgh


Sufficiency level cities are cities that have a sufficient degree of services so as not to be overtly dependent on world cities. Examples are La Paz and Jerusalem.

Source:
https://en.wikipedia.org/wiki/Global_...
https://www.citylab.com/life/2017/01/...