### Question
How is the "city pair" defined?


### Answer
The term **city pair** is defined in *39 U.S.C. § 5402* as follows -

> service between an origin and destination city pair

#### Citation:
  - *39 U.S.C. § 5402*
  - Heading: **PART V-TRANSPORTATION OF MAIL > CHAPTER 54-TRANSPORTATION OF MAIL BY AIR**

