Latin: by what authority?
A challenge to a person allegedly improperly asserting a right to hold a public office.
The writ seeks to disenfranchise on the record a person or organization from doing something for which it may not have the legal authority, by demanding to know by what right they exercise the controversial authority.
Challenging a person's right to hold a public office.
As with the related remedies of mandamus, certiorari and prohibition, these remedies have been displaced by many jurisdictions and replaced by more generic-named tools such as injunctions or judicial review.