ecumenopolitan · adjective, noun1
From ecumenopolis + -ity + -an. First reliably attested in 1974: either, as from Ecumenopolitan, or a generalised use thereof, parallel with the development of ecumenopolis.
Ecumenopolitan · adjective, noun2
Adjectival sense first attested in 1969; nominal sense in 1977: Ecumenopolis + -itan, formed on the pattern of megalopolitan, necropolitan.
Etymology from Wiktionary, CC BY-SA 4.0.