North, South, East and West qualifiers

 I’m from New England and I live in California. When I refer to my native home, I say “back east,” and when I’m home and referring to my adopted city of Los Angeles, I say, “out west.” You would never say “back west” or “out east.” How did these conventions begin? 

“Back east” and “out west” emerged at approximately the same time, and as you might guess, it was during the western expansion of the United States. The east was the settled area, the known quantity. If you were going west, you were going out west, into the unknown, and if you were coming back, you were headed back east, returning to the familiar. In most sentences, these expressions will serve as adverbs, as they typically modify the verb. In the sentence, "I am going back east," the word "back" offers more details on the verb, "going." If you answer the question, "Where in the heck is he?" by simply saying, "Back East," the word "back" behaves as a preposition.

 

So what of the other chief compass points? It’s “up north” or “down south,” obviously because of a map’s orientation. The word “up” probably ought to refer to a direction away from the center of the Earth, while the word “down” ought to indicate a direction towards it. Our frame of reference for North and South is a physical positioning of up and down, whereas at least as far as adverbial expressions go, the East and West seem more to be derived from a frame of mind.