U1, U.I or U-1 may refer to:

Mathematics

*U(1), the degree one ''

unitary group In mathematics, the unitary group of degree ''n'', denoted U(''n''), is the group of unitary matrices, with the group operation of matrix multiplication. The unitary group is a subgroup of the general linear group . Hyperorthogonal group is ...

Military

*U-1, the

USAF The United States Air Force (USAF) is the Aerial warfare, air military branch, service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part ...

and

US Military The United States Armed Forces are the Military, military forces of the United States. The armed forces consists of six Military branch, service branches: the United States Army, Army, United States Marine Corps, Marine Corps, United States N ...

's designation for the

De Havilland Canada DHC-3 Otter The de Havilland Canada DHC-3 Otter is a single-engined, high-wing, propeller-driven, short take-off and landing (STOL) aircraft developed by de Havilland Canada. It was conceived to be capable of performing the same roles as the earlier and h ...

light transport aircraft *U-1, Soviet designation for

Avro 504 The Avro 504 was a First World War biplane aircraft made by the Avro aircraft company and under licence by others. Production during the war totalled 8,970 and continued for almost 20 years, making it the most-produced aircraft of any kind tha ...

trainer. *Multiple German U-boats named ''U-1'' *

Oberursel U.I __NOTOC__ The Oberursel U.I was an early German aircraft engine that powered many German fighter aircraft in the first part of World War I. It was a 9-cylinder air-cooled rotary engine, a licence-built copy of the Gnome DeltaKyrill von Gersdorff ...

, an early German aircraft engine *

HDMS U-1 ORP ''Dzik'' (Boar) was a U-class submarine built by Vickers-Armstrong at Barrow-in-Furness. She was laid down on 30 December 1941 as P-52 for the Royal Navy, but was transferred to the Polish Navy during construction. Launched on November ...

, a Danish submarine * SM U-1, an Austro-Hungarian submarine, lead ship of the U-1 class

Entertainment

* U1 Technology, a game and software developing company *'' Ultima I: The First Age of Darkness'', a 1981 video game

People

* U1, alias for

Yuvan Shankar Raja Yuvan Shankar Raja or Abdul Haliq (born 31 August 1979) is an Indian film score and soundtrack composer and singer-songwriter. He mainly scores music for Tamil films. Considered a versatile composer, he is particularly known for his use of Wes ...

(born 1979), a Tamil musician and film composer *U-1, the main character in the video game '' Gitaroo Man'' for the PlayStation 2/PlayStation Portable

Railways

* LNER Class U1, a 1924 British solitary 2-8-0+0-8-2 Beyer-Garratt locomotive *

SR U1 class The SR U1 class were three-cylinder 2-6-0 ('mogul') steam locomotives designed by Richard Maunsell for passenger duties on the Southern Railway. The fifth member of the Maunsell "family" of standardised moguls and 2-6-4 locomotives, the U1 was ...

, a class of 2-6-0 locomotives developed from the U Class

U-Bahn lines

* U1 (Berlin U-Bahn) *

U1 (Frankfurt U-Bahn) The A line is the north-to-south main line of the Frankfurt U-Bahn. It is the oldest and longest line of the U-Bahn system. Served by four routes (U1, U2, U3 and U8) starting at ''Südbahnhof Railway Station'' in Sachsenhausen, the A line runs thr ...

* U1 (Hamburg U-Bahn) *

U1 (Munich U-Bahn) The Munich U-Bahn (german: U-Bahn München) is an electric rail rapid transit network in Munich, Germany. The system began operation in 1971, and is operated by the municipally owned Münchner Verkehrsgesellschaft (MVG; Munich Transport Company ...

U1 (Nuremberg U-Bahn) The U1 is an underground line in Nuremberg. The first part of the line was opened on 1 March 1972. It is about long and has 27 stations. The termini are Langwasser Süd in the southeast and Fürth Hardhöhe in the northwest. Until 11 Decembe ...

U1 (Vienna U-Bahn) Line U1 is a line on the Vienna U-Bahn metro system. Opened in 1978, it currently has 24 stations and a total length of , from to . When the extension to Oberlaa was completed in 2017, the line became the longest on the network, surpassing the ...

Technology

Secure Digital Secure Digital, officially abbreviated as SD, is a proprietary non-volatile flash memory card format developed by the SD Association (SDA) for use in portable devices. The standard was introduced in August 1999 by joint efforts between SanD ...

(SD) Cards, class of speed *

Apple U1 Apple silicon is a series of system on a chip (SoC) and system in a package (SiP) processors designed by Apple Inc., mainly using the ARM architecture. It is the basis of most new Mac computers as well as iPhone, iPad, iPod Touch, Apple T ...

Other

*U1, unemployment figure released by Bureau of Labor Statistics *

U1 spliceosomal RNA U1 spliceosomal RNA is the small nuclear RNA (snRNA) component of U1 snRNP (''small nuclear ribonucleoprotein''), an RNA-protein complex that combines with other snRNPs, unmodified pre-mRNA, and various other proteins to assemble a spliceosome, a ...

, a small nuclear RNA component of the spliceosome involved in pre-mRNA splicing.