Architecture is the practice of building design and its resulting products; customary usage refers only
to those designs and structures that are culturally significant. Architecture is to building as literature
is to the printed word. Vitruvius, a 1st-century BC Roman, wrote encyclopedically about architecture,
and the English poet Sir Henry Wotton was quoting him in his charmingly phrased dictum: “Well
building hath three conditions: Commoditie, Firmenes, and Delight.” More prosaically, one would
say today that architecture must satisfy its intended uses, must be technically sound, and must convey
aesthetic meaning. But the best buildings are often so well constructed that they outlast their original
use. They then survive not only as beautiful objects, but as documents of the history of cultures,
achievements in architecture that testify to the nature of the society that produced them. These
achievements are never wholly the work of individuals. Architecture is a social art.
Architectural form is inevitably influenced by the technologies applied, but building technology is
conservative and knowledge about it is cumulative. Precast concrete, for instance, has not rendered
brick obsolete. Although design and construction have become highly sophisticated and are often
computer directed, this complex apparatus rests on preindustrial traditions inherited from millennia
during which most structures were lived in by the people who erected them. The technical demands
on building remain the elemental ones – to exclude enemies, to circumvent gravity, and to avoid
discomforts caused by an excess of heat or cold or by the intrusion of rain, wind, or vermin. This is
no trivial assignment even with the best modern technology.
The availability of suitable materials fostered the crafts to exploit them and influenced the shapes
of buildings. Large areas of the world were once forested, and their inhabitants developed carpentry.
Although it has become relatively scarce, timber remains an important building material.
Many kinds of stone lend themselves to building. Stone and marble were chosen for important
monuments because they are incombustible and can be expected to endure. Stone is also a sculptural
material; stone architecture was often integral with stone sculpture. The use of stone has declined,
however, because a number of other materials are more amenable to industrial use and assembly.
Some regions lack both timber and stone; their peoples used the earth itself, tamping certain
mixtures into walls or forming them into bricks to be dried in the sun. Later they baked these
substances in kilns, producing a range of bricks and tiles with greater durability.

According to the passage, the term “architecture” is normally used to refer to the
designs and structures that have ______.