O9 Explained
O9 or O-9 may refer to:
- USS O-9 (SS-70), an O-class submarine of the United States Navy
- O-9, the pay grade for the following senior officer ranks in the U.S. uniformed services:
- Lieutenant General in the Army, Marine Corps, Air Force, and Space Force
- Vice Admiral in the Navy, Coast Guard, Public Health Service Commissioned Corps, and NOAA Commissioned Officer Corps
- Douglas O-9, a variant of the Douglas O-2, a 1920s American observation aircraft
- O9 (model railways)
See also
