A spire is a tall, slender, pointed structure on top of a roof of a building or tower, especially at the summit of church steeples. A spire may have a square, circular, or polygonal plan, with a roughly conical or pyramidal shape. Spires are typically made of stonework or brickwork, or else of timber structures with metal cladding, ceramic tiling, roof shingles, or slates on the exterior.
Since towers supporting spires are usually square, square-plan spires emerge directly from the tower's walls, but octagonal spires are either built for a pyramidal transition section called a broach at the spire's base, or else freed spaces around the tower's summit for decorative elements like pinnacles. The former solution is known as a broach spire. Small or short spires are known as spikes, spirelets, or flèches.