Adjutant is a military rank or appointment. In some armies, including most English-speaking ones, it is an officer who assists a more senior officer, while in other armies, especially Francophone ones, it is an NCO (non-commissioned officer), normally corresponding roughly to a Staff Sergeant or Warrant Officer.
An Adjutant General is commander of an army's administrative services.
Read more about Adjutant: Etymology, Military and Paramilitary Appointment, Non-Commissioned Rank, Adjutant General