situated in or oriented toward the northeast
"the northeasterly part of the island"
of a region of the United States generally including the New England states; New York; and sometimes New Jersey and Pennsylvania
"The northeastern states have a rich history of industrial development."
Of, related to, located in, or from the northeast.
"The northeastern corner of the state is known for its rugged coastline."
In plain English: Northeastern describes something located toward both north and east directions on a map.
"The restaurant in our northeastern corner serves excellent pizza every evening."
Usage: Use this adjective before nouns like Northeastern University or northeastern winds, but capitalize it only when referring specifically to that region of the United States as a proper noun. Avoid confusing it with "north-easterly," which describes direction rather than location or affiliation.
Northeastern comes from the combination of the words north and east, which were joined together in Old English to describe a direction between those two points. The term traveled directly into Middle English without changing its fundamental meaning or structure.