Definition of bureau of investigation in US English:

bureau of investigation

noun

  • 1Originally and chiefly US an organization or institution which carries out investigations or studies in a particular field or industry (now rare).

  • 2US (with the and capital initials) an office of the Department of Justice responsible for investigating violations of federal laws (now historical).

Origin

Mid 19th century; earliest use found in Hartford (Connecticut) Daily Courant.