Arch in the context of "Lintel"

Ancient Roman architecture adopted the external language of classical ancient Greek architecture for the purposes of the ancient Romans, but was different from Greek buildings, becoming a new architectural style. The two styles are often considered one body of classical architecture. Roman architecture flourished in the Roman Republic and to an even greater extent under the Empire, when the great majority of surviving buildings were constructed. It used new materials, particularly Roman concrete, and newer technologies such as the arch and the dome to make buildings that were typically strong and well engineered. Large numbers remain in some form across the former empire, sometimes complete and still in use today.

Roman architecture covers the period from the establishment of the Roman Republic in 509 BC to about the 4th century AD, after which it becomes reclassified as Late Antique or Byzantine architecture. Few substantial examples survive from before about 100 BC, and most of the major survivals are from the later empire, after about 100 AD. Roman architectural style continued to influence building in the former empire for many centuries, and the style used in Western Europe beginning about 1000 is called Romanesque architecture to reflect this dependence on basic Roman forms.

The Roman architectural revolution, also known as the concrete revolution, is the name sometimes given to the widespread use in Roman architecture of the previously little-used architectural forms of the arch, vault, and dome. For the first time in Europe, possibly in the world (earlier experiments with arches in Ancient Egypt and Mesopotamia notwithstanding), the potential of these elements was fully appreciated and exploited in the construction of a wide range of civil engineering structures, public buildings, and military facilities. Throughout the Roman Empire, from Syria to Scotland, engineers erected structures using semicircular arches. The first use of arches was for civic structures, like drains and city gates. Later the arches were utilized for major civic buildings bridges and aqueducts, with the outstanding 1st century AD examples provided by the Colosseum, Pont Du Gard, and the aqueduct of Segovia. The introduction of the ceremonial triumphal arch dates back to Roman Republic, although the best examples are from the imperial times (Arch of Augustus at Susa, Arch of Titus).

A crucial factor in this development that saw a trend to monumental architecture was the invention of Roman concrete (also called opus caementicium), which led to the liberation of the shape from the dictate of the traditional materials of stone and brick.

A tympanum (pl. tympana; from Greek and Latin words meaning "drum") is the semi-circular or triangular decorative wall surface over an entrance, door or window, which is bounded by a lintel and an arch. It often contains pedimental sculpture or other imagery or ornaments. Many architectural styles include this element, although it is most commonly associated with Romanesque and Gothic architecture.

Alternatively, the tympanum may hold an inscription, or in modern times, a clock face.

A keystone species is a species that has a disproportionately large effect on its natural environment relative to its abundance. The concept was introduced in 1969 by the zoologist Robert T. Paine. Keystone species play a critical role in maintaining the structure of an ecological community, affecting many other organisms in an ecosystem and helping to determine the types and numbers of various other species in the community. Without keystone species, the ecosystem would be dramatically different or cease to exist altogether. Some keystone species, such as the wolf and lion, are also apex predators.

The role that a keystone species plays in its ecosystem is analogous to the role of a keystone in an arch. While the keystone is under the least pressure of any of the stones in an arch, the arch still collapses without it. Similarly, an ecosystem may experience a dramatic shift if a keystone species is removed, even though that species was a small part of the ecosystem by measures of biomass or productivity.It became a popular concept in conservation biology, alongside flagship and umbrella species. Although the concept is valued as a descriptor for particularly strong inter-species interactions, and has allowed easier communication between ecologists and conservation policy-makers, it has been criticized for oversimplifying complex ecological systems.

In architecture, a vault (French voûte, from Italian volta) is a self-supporting arched form, usually of stone or brick, serving to cover a space with a ceiling or roof. As in building an arch, a temporary support is needed while rings of voussoirs are constructed and the rings placed in position. Until the topmost voussoir, the keystone, is positioned, the vault is not self-supporting. Where timber is easily obtained, this temporary support is provided by centering consisting of a framed truss with a semicircular or segmental head, which supports the voussoirs until the ring of the whole arch is completed.

The Mycenaeans (ca. 1800–1050 BC) were known for their tholos tombs, also called beehive tombs, which were underground structures with conical vaults. This type of vault is one of the earliest evidences of curved brick architecture without the use of stone arches, and its construction represented an innovative technique for covering circular spaces.

In architecture, a semicircular arch is an arch with an intrados (inner surface) shaped like a semicircle. This type of arch was adopted and very widely used by the Romans, thus becoming permanently associated with Roman architecture.

The ancient Romans were the first civilization to build large, permanent bridges. Early Roman bridges used techniques introduced by Etruscan immigrants, but the Romans improved those skills, developing and enhancing methods such as arches and keystones. There were three major types of Roman bridge: wooden, pontoon, and stone. Early Roman bridges were wooden, but by the 2nd century BC stone was being used. Stone bridges used the arch as their basic structure, and most used concrete, the first use of this material in bridge-building.

A triumphal arch is a free-standing monumental structure in the shape of an archway with one or more arched passageways, often designed to span a road, and usually standing alone, unconnected to other buildings. In its simplest form, a triumphal arch consists of two massive piers connected by an arch, typically crowned with a flat entablature or attic on which a statue might be mounted or which bears commemorative inscriptions. The main structure is often decorated with carvings, sculpted reliefs, and dedications. More elaborate triumphal arches may have multiple archways, or in a tetrapylon, passages leading in four directions.

Triumphal arches are one of the most influential and distinctive types of ancient Roman architecture. Effectively invented by the Romans, and using their skill in making arches and vaults, the Roman triumphal arch was used to commemorate victorious generals or significant public events such as the founding of new colonies, the construction of a road or bridge, the death of a member of the imperial family or the accession of a new emperor.