"Keystone" vs. "cornerstone": building blocks with a twist

Reviewed and edited by

Lloyd Cooper Today, 19:39

English.me team member

Keystone and cornerstone. What's the difference?

What is similar?

Both "keystone" and "cornerstone" refer to something that is essential, foundational, or central to the success or integrity of a structure, concept, or system. They are both often used metaphorically to describe crucial elements in non-literal contexts.

What is different?

"Keystone" originally refers to the central, wedge-shaped stone at the top of an arch, holding the other stones in place. Metaphorically, it suggests something that holds together or is the critical element of a structure or system. "Cornerstone" refers to the first stone set during the construction of a foundation, important for the stability and orientation of the entire building. Metaphorically, it suggests an initial and fundamental element upon which something is based or constructed.

Which one is more common?

Examples of usage

Keystone

Education is the keystone of a healthy democracy.
Trust serves as the keystone for all successful relationships.

Cornerstone

Honesty is the cornerstone of their business philosophy.
The groundbreaking ceremony marked the laying of the new library's cornerstone.