A flat stone, thin in relation to its surface area, that may be used as a stepping stone, for a terrace or patio, or for floor paving. Usually either naturally thin or split from rock that cleaves readily.
Flagstone is a type of flat stone, usually used for paving slabs, but also for making fences or roofing. It may also be used for making memorials or headstones in a cemetery. It also refers to Pennsylvania Bluestone, a stone from northeastern Pennsylvania and the southhern tier of New York.