4O or 4-O may refer to:
*
Quarto (4° or 4o), a format of a book
*
4 Degrees and Beyond International Climate Conference
The 4 Degrees and Beyond International Climate Conference, subtitled ''Implications of a Global Climate Change of 4+ Degrees for People, Ecosystems and the Earth-system'', was held 28–30 September 2009 at Oxford, United Kingdom. The three-day c ...
, 2009
*
Quaternary sector of the economy (4o Sector)
*
Air Montenegro
To Montenegro a.d (stylised as ''ToMontenegro'' and ''2Montenegro''), is the flag carrier of Montenegro, which is branded and operates under the name Air Montenegro (Montenegrin Cyrillic: Ер Монтенегро), a new company opened in ear ...
(IATA code: 4O), the flag carrier of Montenegro
*
Interjet (former IATA code: 4O), a former Mexican airline
*
2007 Rally d'Italia Sardegna
Results of Rally d'Italia Sardegna (''4º Supermag Rally Italia Sardinia''), 7th round of 2007 World Rally Championship, was run on May 18–20:
__TOC__
Results
Retirements
* Daniel Carlsson - withdrew right after official rally start, ...
(4º Supermag Rally Italia Sardinia)
See also
*
Fourth (disambiguation)
Fourth or the fourth may refer to:
* the ordinal form of the number 4
* ''Fourth'' (album), by Soft Machine, 1971
* Fourth (angle), an ancient astronomical subdivision
* Fourth (music), a musical interval
* ''The Fourth'' (1972 film), a Sovie ...
(4º)
*
4° (disambiguation)
4° may refer to:
*4°, or Quarto a book or pamphlet produced from full 'blanksheets', each of which is printed with eight pages of text, four to a side
*4°, a reference to a 4-degrees Celsius increase in the global average temperature due to clim ...
*
O4 (disambiguation)
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 ...
{{Letter-NumberCombDisambig