there was a distance decay between my friend and me when he moved to Yorkshire because both of us were so far apart we started talking to each other less and less, we used to be best friends but now we kinda lost touch.
distance decay - The declining intensity of any activity, process or function with increasing distance from its point of origin.
that is the definition we learned in our AP human class though the definition might vary depending on what you are looking for
there is another definition of it on the influences of the spread of culture and its dispersion
