O1 or O-1 may refer to:
Aircraft
*
Cessna O-1 Bird Dog
The Cessna O-1 Bird Dog is a liaison and observation aircraft that first flew on December 14, 1949, and entered service in 1950 as the L-19 in the Korean War. It went to serve in many branches of the U.S. Armed Forces, was not retired until t ...
, an observation aircraft manufactured by Cessna
*O-1
Curtiss Falcon
The Curtiss Falcon was a family of military biplane aircraft built by the American aircraft manufacturer Curtiss Aeroplane and Motor Company during the 1920s. Most saw service as part of the United States Army Air Corps as observation aircraft ...
, an observation aircraft manufactured by the Curtiss Aircraft Company
*
O-1 Airship, an Italian manufactured semi-rigid airship operated by the US Navy
Music
*
''O1'' (Hiroyuki Sawano album), 2015
*
''O1'' (Son of Dave album), 2000
Military
*O-1 or ''fenrik'', a
second lieutenant rank in Norway
* The
pay grade
A pay grade is a unit in systems of monetary compensation for employment. It is commonly used in public service, both civil and military, but also for companies of the private sector. Pay grades facilitate the employment process by providing a f ...
for ensign and second lieutenant ranks in the U.S. uniformed services
*
USS ''O-1'' (SS-62), lead ship of the United States O class submarines
*
HNLMS ''O 1'', a 1905 Royal Netherlands Navy O class submarine
Science and technology
* , or
atomic oxygen
There are several known allotropes of oxygen. The most familiar is molecular oxygen (), present at significant levels in Earth's atmosphere and also known as dioxygen or triplet oxygen. Another is the highly reactive ozone (). Others are:
* Atomic ...
* O1 type star, a subclass of
O-type star
An O-type star is a hot, blue star of spectral type O in the Yerkes classification system employed by astronomers. They have surface temperatures in excess of 30,000 kelvins (K). Stars of this type have strong absorption lines of ionised h ...
*
O-1 tool steel, a type of oil-hardening tool steel
*
Haplogroup O1 (Y-DNA), a Y-DNA haplogroup
* O1: an EEG electrode site according to the
10–20 system
* O(1),
time complexity
In theoretical computer science, the time complexity is the computational complexity that describes the amount of computer time it takes to run an algorithm. Time complexity is commonly estimated by counting the number of elementary operations ...
expressed using Big O notation
*
OpenAI o1
OpenAI o1 is a reflective generative pre-trained transformer (GPT). A preview of o1 was released by OpenAI on September 12, 2024. o1 spends time "thinking" before it answers, making it better at complex reasoning tasks, science and programming th ...
, AI model released by OpenAI
Other
* O-1 visa, a variety of the U.S.
O visa
An O visa is a classification of non-immigrant temporary worker visa granted by the United States to an alien "who possesses extraordinary ability in the sciences, arts, education, business, or athletics, or who has a demonstrated record of e ...
, allowing for temporary immigration for work purposes for individuals of extraordinary ability or achievement in certain areas
*
Otoyol 1
Otoyol 1 (), abbreviated as O-1 and locally referred to as The First Beltway (), is a controlled access highway in Istanbul, Turkey. The O-1 serves as the inner beltway and is one of three intercontinental motorways in the city, the others being t ...
, a motorway in Turkey
*
Ö1
Österreich 1 (Ö1) is an Austrian radio station: one of the four national channels operated by Austria's public broadcaster ORF. It focuses on classical music and opera, jazz, documentaries and features, news, radio plays and dramas, ''Kabarett ...
, an Austrian radio station
* O1 Communications, Inc., a California telecommunications company
*
Orchestra ONE (O1), an experimental youth orchestra based in Maidstone, United Kingdom
*
GNR Class O1, a class of British 2-8-0 steam locomotive designed by Nigel Gresley (later redesignated Class O3)
*
LNER Thompson Class O1, a class of British 2-8-0 steam locomotive designed by Edward Thompson and rebuilt from Class O4
See also
*
01 (disambiguation)
*
1O (disambiguation)
1O or 1-O or 1º (the digit "1" and the letter "O") may refer to:
*1º Sector, the primary sector of the economy
*2017 Catalan independence referendum, called for 1 October 2017, known as 1-O
See also
*
*1º de Mayo (disambiguation)
*10 (dis ...
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