Holy Trinity Church
St Nicholas' Church
The word church is frequently used to describe a building used for prayer, worship, or other public religious services, usually referring specifically to those for Christian worship.
A common architecture for churches is the shape of a cross, a long central rectangle, with side rectangles, and a rectangle in front for the altar space or sanctuary. These churches also often have a dome or other large vaulted space in the interior to represent or draw attention to the heavens. Other common shapes for churches include a circle, to represent eternity, or an octagon or similar star shape, to represent the church's bringing light to the world. Another common feature is the spire, a tall tower on the "west" end of the church or over the crossing.
A cathedral is a church, usually Roman Catholic, Anglican, or Eastern Orthodox, housing the seat of a bishop. The word cathedral takes its name from the word cathedra, or Bishop's Throne. The term is often (sometimes improperly) used to refer to any church of great size.
The church that has the function of cathedral is not of necessity a large building. It might be as small as Christ Church Cathedral, Oxford. But frequently, the cathedral, along with some of the abbey churches, was the largest building in any region.