Word Meaning

keystone definition and meaning

n. The central or topmost stone of an arch. This in some styles is made different in size from the other voussoirs, or projects, or is decorated with carving. See Illust. of Arch.

Crossword clues for keystone

- Arch's principal surmounting piece
- Central part of a policy or system
- Central piece atop an arch
- Essential principle
- Wedge-shaped piece occupying an arch's centre