Special combinations of columns, base, shaft and capital, and the entablature above, evolved to be known as orders. Invented by the Greeks, and used and adapted by the Romans, they were revived in the Renaissance. The earliest was the Doric (Dorian tribes) followed by the Ionic (Ionians) and the Corinthian. The Romans added two more, the Tuscan (Etruscans) and the Composite orders. Each order has its own peculiar decoration and proportional relationship between its various parts. The size of buildings may vary, but these proportional relationships stay constant. Eventually the orders became personalised, with the sturdy Doric and Tuscan seen as representing the masculine figure, the more slender Ionic the older woman, the matron, and the graceful Corinthian and Composite, the younger woman, the maiden.
The Romans continued to build in the tradition of the Greeks, devising their own orders, but their needs were different, they made use of the arch (see arcuated) and where the Greeks seldom used mortar, the Romans developed cements and concretes which allowed them to fully exploit rounded forms. They often built to four and five storeys, as opposed to the Greeks two, and the orders steadily became more decorative than functional.
Abacus - the flat slab which sits on top of a capital.
Architrave - the lowest of the three main horizontal divisions of the entablature.
Attic base - the base of an Ionic column, which consists of two convex mouldings, the top one being smaller, separated by a concave moulding.
Capital - the crowning feature or head of a column or pilaster.
Column - in classical architecture, a column consists of a base, shaft and a capital. An engaged column projects about half its thickness from a wall.
Cornice - the top, projecting, horizontal division of the entablature.
Crepidoma - the base on which a classical temple sits.
Echinus - a convex moulding forming part of the capital in doric and ionic orders, below the abacus.
Entablature - the upper part of an order, consisting of cornice, frieze and architrave. Essentially the beam which spans between columns. Literally it means something laid upon a table, ie flat.
Fascia - a plain horizontal band in an architrave.
Frieze - the middle division of the entablature, usually heavily decorated.
Guttae - small projections under the triglyphs in a doric frieze. Said to represent pegs used in the original timber construction.
Metope - the square space between triglyphs in a doric frieze.
Modillions - small brackets, usually in pairs, which supports the cornice of the corinthian and composite orders.
Necking - a narrow moulding between the base and shaft of a column.
Stylobate - the top step of the crepidoma.
Triglyph - the blocks with vertical grooves separating the metopes in a doric frieze. Said to represent beam ends.
Volute - a spiral scroll, found on the capital of the ionic order. The centre is often referred to as the "eye".
The Orders - Order is a good term in this context, it implies both an acceptable organisation of component parts and a satisfying relationship between them. A colossal or giant order is any order, the columns of which extend through more than one floor.
The most massive and probably the oldest of the orders. The Greek doric had no base, the Romans added one. Shafts are fluted, numbers vary, but there are usually around twenty. The height of the column is between four-and-and-a-quarter and eight diameters. The entablature is around a quarter of the height of the order. Decoration is copied from timber construction, the cornice projects strongly, the frieze is divided into metopes and triglyphs, the architrave is usually plain.
Confined mainly to the north of Italy, it was employed by the Romans but replaced by the doric. Very plain, the columns are not fluted, and in height it is usually around seven diameters.
Later than the doric, the ionic order has a distinctive capital, with two volutes, and an echinus based on a water lily shape. The Greek capital was straight sided, the volutes on the Roman capital angled outwards. The columns, on attic bases, usually have about twenty four flutes, and are between eight and nine diameters in height. The entablature is usually about one-fifth of the whole. The cornice projects and often has dentil ornamentation, the frieze can be decorated, the architrave is usually divided into three fascias.
Invented by the Greeks, but not widely used, it was developed by the Romans. The capital has acanthus leaf decoration, which legend bases on a hanging basket. The columns are usually ten diameters in height. The entablature is heavily decorated, with a particularly deep cornice, usually supported on modillions.
Developed by the Romans, the composite is a mixture of the ionic and corinthian orders. Usually ten-and-a-half diameters in height, the order was richly ornate and was mainly used on triumphal arches.