This European Standard provides a dictionary of the possible components of postal addresses, together with examples of and constraints on their use. It also defines a number of useful terms, such as delivery address, forwarding address, mailee and mail originator. It does not specify the length or value range of components. Nor, though it may indicate some cases in which a component may occur more than once, does it give a precise specification of recurrence rules. NOTE 1 An individual postal address, or a class of postal addresses (such as the addresses used in a given country) may require only a subset of the possible components. For example, Irish postal addresses do not include postcode; Dutch addresses do not separate thoroughfare type from thoroughfare name. The standard is an enabling one: it serves to define components that are drawn on in other standards described in the Introduction above. It is intended to be used together with the other parts of the standard. The standard defines three levels of postal address component: a) elements, such as organisation name or legal status, which correspond to the lowest level of component which it may be useful (A.1) to distinguish in address representations; b) constructs, such as organisation identification, which group elements into units which are more meaningful for human interpretation; c) segments, such as addressee specification, which correspond to major logical portions of a postal address. By providing a standard dictionary of postal address components, this standard is expected to greatly facilitate the formal description of actual address representations and the definition of procedures for mapping between them. In practice, many address representations, whether in computer databases, in electronic messages or in printed or written form, may combine several of the postal address components defined herein into single fields or lines.