^^^Well this article has nothing to do with selling or marketing the City of Jacksonville...and I doubt is anything you'd ever pass on to someone. Also, this website isn't in the business of phrasing articles according to how you may or may not communicate with foreigners. There is absolutely nothing cut and dry with describing the size of a "city" on any continent. Few people anywhere I'm sure think of a city only by its city limits (for instance, Jacksonville is not really the "biggest city in FL" and if anyone ever gives it any sort of brainpower at all beyond reading a stupid arbitrary stat on paper, nobody is concluding that Jacksonville is bigger than Miami). So I think "city" is a pretty interchangeable phrase that means more or less the same thing to most lay people.
Atlanta is a big city.
Nobody is taking that statement to mean the jagged city boundaries that encompass 400,000 people is "big". I think people take that to mean that Atlanta and its surroundings (which is what people think of when they think of Atlanta) is big, and encompasses millions of people. To most people, they don't know or care how many millions, but it's abundantly clear that Atlanta is one of the biggest "cities" in America, with millions of people. There are really only a few American cities that look, feel, and act their actual size per considerations of the global stage no matter how their stats are broken down (NYC, Chicago, Boston, Philly, SF, DC, Seattle, and LA). Any other cities are probably just going to confuse the hell out of foreigners anyway.
I'm sure those foreigners you speak of are utterly confused if you stick to city limits and tell them Jax has 900K people, which in their mind should look something like Prague or Stockholm. Perhaps you say Metro of 1.4 million. Still means in their mind it should look something like Prague or Stockholm. Either way, I'm sure, is super confusing to foreigners who come to the city and are wondering where "the city" is.
I digress...I thought today's article was very clear, and nothing changes no matter what stats or words on paper you decide to use. Jacksonville is the largest city in America, perhaps the entire Starbucks global footprint, without a Starbucks in its downtown area.