O4

Look up o4 in Wiktionary, the free dictionary.

O4 may refer to:

  • LNER Class O4, a class of ex-Great Central Railway 2-8-0 steam tender locomotives
  • Taff Vale Railway O4 class, a class of 0-6-2T steam tank locomotives
  • USS O-4 (SS-65), a 1917 United States O class submarine
  • O-4, the pay grade for the following officer ranks in the U.S. uniformed services:
    • Major in the Army, Marine Corps, Air Force, and Space Force
    • Lieutenant Commander in the Navy, Coast Guard, Public Health Service Commissioned Corps, and NOAA Commissioned Officer Corps
  • Tetraoxygen (O4), oxozone
  • a class of stars in the stellar classification
  • Otoyol 4, a highway from Istanbul to Ankara, Turkey
  • Martin XO-4, an observation aircraft proposed by the Glenn L. Martin Company
  • O(4), the orthogonal group in dimension 4

See also

  • 04 (disambiguation)
  • 4O (disambiguation)
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