Large format means a negative size of 20 square inches or larger. Period. 4x5 cropped to 19.5 square inches is not LF.
One man's Mede is another man's Persian.
Ahh... okay. Then 4x5in isn't large format because the film holder crops it in-camera to 17.8125 square inches.
BTW, I'm mostly playing here... just being facetious... mostly.
“Wise men talk because they have something to say; fools, because they have to say something.” - Plato