The phrase "northeast corner" refers to a specific location on a map or in real life, which is at the intersection of the northeasternmost point and the vertical line that separates the north and east directions. In other words, it is the area where the two imaginary lines meet when traveling from north to south or from east to west. This term can also be used to describe a physical location in real life, such as a building or landmark that is situated at this point on a map.