The story
From metro (“metropolitan”) + Toronto. From being the metropolitan urbanized zone around Toronto.
Etymology from Wiktionary, CC BY-SA 4.0.
Metro Toronto
Today it means: A former supramunicipal government that existed in the late 20th century, composed of the former cities of Etobicoke, Scarborough, York, North York, East York, Toronto; which was merged into the 21st century city of Toronto, with six boroughs composed of the former cities of the merger. Full definition →