Defines key terms for postal addressing, postal address components and constraints on their use. Specifically, the standard defines postal address components organized into three hierarchical levels: elements, such as organization name or postcode, which have well-defined conceptual meaning and are not themselves made up of subordinate components, though they may be sub-divided for technical purposes; constructs, such as organization identification, which group elements into units form a logical portion of a postal address; segments, such as addressee specification, which group-related postal address constructs and/or postal address elements into units with a specific defined function. This standard also specifies a mechanism for creation of sub-elements, which correspond to either sub-divisions of element content, such as door type or door indicator or to multiple occurrences and locations of elements in an address, such as levels of administrative regions.
