It means big cities, gigantic cities, big metropolises, cities, metropolises.
City of very large size, also called megalopolises. From Greek 956; 949; 947; 945; 962; or 956; 949; 947; 945; 955; 951; (megas or megalé "big, big" ) 960; 959; 955; 953; 962; (polys "city" ) . See mega, metropolis, metropolis.