Midtown, along with "Uptown" and "Downtown", is one of the three major subdivisions of Manhattan (though "Uptown" and "Downtown" can also be used as adjectives or prepositions, and can take on completely different meanings in the other boroughs, whereas the term "Midtown" cannot) and can be understood as those parts of Manhattan in neither of these two other regions - that is, all areas between 14th Street and 59th Street, from the Hudson River to the East River, about five square miles or 12 km2. The core of Midtown Manhattan is from about 31st Street to 59th Street between Third and Ninth avenues, about two square miles (this is the area most commonly referred to as "Midtown.") The "Plaza District", a term used by Manhattan real estate professionals to denote the most expensive area of midtown from a commercial real estate perspective, lies between 42nd Street and 59th Street, from Third Avenue to Seventh Avenue, about a square kilometer or half a square mile.