1936 C. B. Fawcett in B. Salamon & K. Kuchar 52 A ‘millionaire-city’ is to be understood as a conurbation which contains at least one million inhabitants.
1958 43 258 The emergence of millionaire cities and even five-million cities in tropical countries is now widespread and continuing.
2000 (Nexis) 11 Jan. 26 Many of the world's largest cities have satellite ‘millionaire’ cities within one urban area.