`  Just on my first search I found http://www.defenselink.mil/specials/insignias/officers.html. In general (no pun intended), the US military refers to all generals and admirals as ``flag grade`` officers (all of them have flags associated with their rank and branch of service). The remaining grades of officers are company grade (O-1 through O-3; this translates to Lieutenants in the Army, Air Force, and Marines and Ensigns and Lieutenants in the Navy), and field grade (O-4 thought O-6; Majors, Lieutenant Colonels, & Colonels in the Air Force, Army, & Marines and Lieutenant Commanders, Commanders, and Captains in the Navy).`