An imprimatur is official approval or permission, especially for something to be published or made public. The word originally came from the Catholic Church's system of reviewing books: before a religious text could be printed, church authorities would examine it and, if they approved, stamp it with the Latin word imprimatur, meaning “let it be printed.”

Today the word has a broader meaning. When a respected organization gives its imprimatur to a project, it's saying, “Yes, this meets our standards.” A principal might give her imprimatur to a student newspaper before it's distributed. A museum director's imprimatur signals that an exhibition is ready for the public.

The word suggests more than casual approval. Getting someone's imprimatur means receiving their official stamp of authority, their formal blessing that something is acceptable or worthwhile. When a famous scientist gives her imprimatur to a young researcher's work, she's putting her reputation behind it. Without the coach's imprimatur, the team can't use the new practice schedule.

Notice that an imprimatur usually comes from someone with real authority: a leader, an expert, or an institution that others respect and trust.