A postal code is a unique identifier assigned to a grouping of addresses (usually organized geographically). They are represented internationally by letters and numbers, although some countries have stricter schemes (e.g., in the United States, only 5-digit numbers are used). Every valid address has a postal code component to it.
Postal codes were created for organizational purposes – they allow for rapid sortation and distribution of mail. They are also often used for data analysis because they are a convenient and accurate way of grouping individuals; people in the same postal code often share many demographic characteristics.
