1. keystone

noun. ['ˈkiːˌstoʊn'] the central building block at the top of an arch or vault.

Rhymes with Keystone

• freestone

Sentences with keystone

1. Noun, singular or mass
Beavers are so important in ecology that they are known as a keystone species.

2. Adjective
Because they chow down on urchins, sea otters are considered "keystone predators."

Quotes about keystone

1. The philosophic outlook rises above all sectarian controversy. It finds its own position not only by appreciating and synthesizing what is solidly based in the rival sects but also by capping them all with the keystone of nonduality.
- Paul Brunton, The Notebooks of Paul Brunton

2. keystone

noun. ['ˈkiːˌstoʊn'] a central cohesive source of support and stability.