Definition of firearms officer in US English:

firearms officer

noun

  • 1A police officer responsible for managing the use of firearms by a police department.

  • 2A police officer responsible for enforcing laws relating to firearms.

  • 3British a police officer who is trained and authorized to carry and use a firearm (frequently with modifying word, especially as "authorized firearms officer").

Origin

1950s; earliest use found in The Washington Post.