Definition of keystone
- determination, a keystone of the puritan ethic
- —L. S. Lewis
Tourism is the city's economic keystone.
the keystone of his faith
These example sentences are selected automatically from various online news sources to reflect current usage of the word 'keystone.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.
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having a quality expressive of sadness
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