The prefixes around here used to indicate what part of town that a number was from. They names standing for prefixes were used around here even after they started adding more digits. The first two letters corresponded to the numbers that the prefix stood for.

Greenfield5-2333 = 475-2333
Skyline7-9444 = 759-9444
All of Washington had the same area code, 206 until 1957 when Eastern Washington was split into 509. It was not until 1995 that they split 206 again by adding 360 for "outlying areas". Then in 1997 they split 206 again into 253 for Tacoma, and 425 for Everett and the East Side of King County. In 2017 564 was added to supplement the number pools which were again being exhausted in Western Washington can be for anyone normally in 206, 253, 360, or 425. Area codes do not mean what they used to just as prefixes no longer refer to a specific location.
Interestingly enough you used to have to look up the prefix around here to make sure that you were not making a long distance call. A friend of mine lived 5 miles away, but his number was long distance, while another firend was 20 miles away and his number was still local. And if you dialed wrong you had to call the operator to make sure that you would not be charged