say it: uhn-PRES-i-den-tid
unprecedented is an adjective meaning "having no precedent; novel". It carries one recorded sense.
having no precedent; novel
“an unprecedented expansion in population and industry”
Definitions, synonyms and semantic relations for unprecedented come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.