Freeways are expressways that usually have free-flowing traffic.
In Marquette, MI, there is a divided highway that's a freeway according to the road signs. Another prespective toward the claim of it being a freeway is that some roads are cutoff from crossing it and it has at-grade junctions with traffic lights.
Around Pennsylvania, roadgeeks refer to the older limited/controlled access highways as expressways, and the newer ones are refered to as freeways.
In Florida, roadgeeks refer to expressways as any controlled/limited access highway; and they use the term freeway for any controlled/limited access highway that's free of charge.
A Jersey freeway is a freeway that has driveways to private property but has almost 100% grade-separated intersections.