Definition of citadel
- the nation's citadel of health research
- —Constance Holden
- a citadel of higher education
We visited a medieval citadel in Italy.
a massive stone citadel continues to command the city of Halifax, Nova Scotia
These example sentences are selected automatically from various online news sources to reflect current usage of the word 'citadel.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.
: a castle or fort that in past times was used to protect the people of a city if the city was attacked
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