Transepts

Transepts are architectural elements primarily in Christian church design, consisting of one or more arms that extend across the main body of the building at right angles to the nave, creating a cruciform floor plan. In the typical plan, the nave runs longitudinally from entrance toward the chancel or choir, while the transepts sweep out to both sides, and the space where they meet the nave is known as the crossing. The crossing may be surmounted by a tower or dome and often serves as a visual focal point. The arrangement forms the horizontal arms of the cross, with the nave and choir forming the vertical axis. Transepts may contain chapels and galleries; their size and form vary. A building can have one transept (single transept) or two (north and south transepts). Some structures include false transepts—projecting bays that resemble transepts but do not extend across the building.

Transepts became common in late antique and medieval church architecture, becoming characteristic of Romanesque and especially Gothic cathedrals. They improved the capacity for altars and processions, aided liturgical function, and enhanced the silhouette of the building. Notable examples include Notre-Dame de Paris and Chartres Cathedral in France, and Canterbury Cathedral and York Minster in England. The transept remains a defining feature of many Western ecclesiastical plans and has influenced the design of other public buildings that adopt cruciform layouts.