unprecedented · adjective
Meanings and examples
Unlike anything known to have happened or existed before in the relevant situation.
The archive received an unprecedented number of enquiries after the collection became available to the public.
An unprecedented agreement allowed the two organisations to share staff while retaining responsibility for their own services.
The scale of the restoration was unprecedented in the museum's history, requiring several departments to work together.
She cautioned against calling the result unprecedented until earlier records had been checked more thoroughly.