architectural style
A classification of a structure's appearance in terms of design vocabulary and historical period.
The architectural style is a classification of a building's appearance and also of its placement in the history of design. In order to belong to a particular style, a building usually has to have been designed during the period when that style was current; exceptions are sometimes made for very close facsimiles, but generally a construction using a long-outdated style is considered to belong to a revival style.
Each structure can be assigned only one style. When a building is a mixture of different styles, it is classified by the style which dominates its overall appearance. The exterior has priority over the interior in determining the dominant style.
Design vocabulary and the period of design work together in establishing style. Similar-looking forms from a much later period are generally a revival style, subject to the close-facsimile exception described above.