Postal codes are strings of numbers (and sometimes letters) that help postal services determine where a piece of mail is being sent to. They help simplify the task of bringing post to its destination. Nations throughout the world use postal codes, and though the systems and formats vary, the common trait is that they all make the postman's job a little easier. These codes indicate the extent of delivery jurisdictions. Every delivery point that falls under the same jurisdiction is one whole postal code, and anything beyond those dividing lines are counted as a different code. Sometimes postal codes are tied to geographical areas or administrative boundaries. Sometimes they're more free-floating. In some cases, they are attached to a specific organization, or even to a single delivery point. In all cases, they are closely tied to and heavily defined by where the postal employee goes when delivering the mail.