Large format these days is taken to be 5x4 and larger, any thing over 10x8 becomes Ultra large format.
Medium Format is now anything on 120 film 645 6x6 cx7, 6x9
Small Format is 35mm, 126 &127 (very little film availabl), and that's about it.
Subminiature - 16mm (again very little film available)
Before WWII anything on 120/620 and smaller was known as Miniature formats.