Keystone

A keystone is a crucial component in an arch, often the central stone at the top that holds the entire structure together. Its design allows it to distribute weight evenly to the surrounding stones, preventing the arch from collapsing. In a broader context, the term "keystone" can refer to any central element or factor that is essential for the stability and integrity of a system, organization, or concept. Just as the keystone is vital for the strength of an arch, a keystone in other contexts denotes something that maintains balance and support.