The main address for a structure or property is the primary postal address assigned to it, or the house number assigned to any major entrance serving the building as a whole. The entire house numbering range on the side of the main address belongs to the main address, even if only one number within that range is actually assigned to the property. A main address does not apply to unassigned house numbers or secondary street-facing entrances or mailboxes unless they form a continuation of the main address number on the same street or roadway.

An address is a locator and not a property of the building. Streets are renamed and renumbered while the building stands, so an address is current rather than permanent and an old one stays valid for the period it applied.

A building with several entrances usually has several addresses. One of them is the main address and the others are recorded beside it rather than replacing it.

An address is not a position. Two buildings can share one address, and a large site can have an address on a street it does not touch, so the address does not locate the building on the map.