The definition of a metro area is an area with at least 100,000 people where at least 50,000 people reside in the core city
However, it's more complicated than that - to find out more go to https://www12.statcan.gc.ca/census-recensement/2021/ref/dict/az/Definition-eng.cfm?ID=geo009
True, although some of the top US cities are deceptive, as they only take in the statistics for the city proper (cities like New Orleans or St. Louis).