In architecture, a pier is an upright support for a superstructure, such as an arch or bridge. The term architecture (from Greek αρχιτεκτονικήarchitektoniki) can be used to mean a process a profession or documentation A superstructure is an upward extension of an existing structure above a baseline An arch is a structure that spans a space while supporting weight (e A bridge is a Structure built to span a Gorge, Valley, Road, railroad track, River, Body of water The cross section of the pier is generally square, or rectangular, although other shapes are also possible. In Geometry, a cross section is the intersection of a body in 2-dimensional space with a line or of a body in 3-dimensional space with a plane etc Classification A square (regular Quadrilateral) is a special case of a Rectangle as it has four right angles and equal parallel sides In Geometry, a rectangle is defined as a Quadrilateral where all four of its angles are Right angles A rectangle with vertices ABCD would be denoted as In medieval architecture, massive circular supports called drum piers, cruciform (cross-shaped), and composite piers are common. Medieval architecture is a term used to represent various forms of Architecture popular in Medieval Europe. Circles are simple Shapes of Euclidean geometry consisting of those points in a plane which are at a constant Distance, called the For the resurrection device/parasite at the Hyperion Cantos see Cruciform (Hyperion Cantos.

In buildings that are designed as a sequence of bays, each window or door opening between piers is considered a single bay. A bay is a module in classical or Gothic architecture the distance between two supports of a vault or the unit of an opening and its framing on a façade