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

People and characters

Yuvan Shankar Raja Yuvan Shankar Raja (born 31 August 1979), is an Indian composer and playback singer. He mainly scores music for Tamil films along with few Telugu, Kannada, and Hindi films. Considered a versatile composer, he is particularly known for his use o ...

(stage name: U1; born 1979), a Tamil musician and film composer *U-1, a fictional character, the protagonist of the '' Gitaroo Man'' video game

Computing and electronics

*U1, a speed class for Secure Digital (SD) cards * Apple U1, a mobile system-on-a-chip *'' Ultima I: The First Age of Darkness'', a 1981 video game * U1 Technology, a video game publisher

Military

*U-1, the

USAF The United States Air Force (USAF) is the Air force, air service branch of the United States Department of Defense. It is one of the six United States Armed Forces and one of the eight uniformed services of the United States. Tracing its ori ...

and

US Military The United States Armed Forces are the military forces of the United States. U.S. federal law names six armed forces: the Army, Marine Corps, Navy, Air Force, Space Force, and the Coast Guard. Since 1949, all of the armed forces, except th ...

's designation for the

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

light transport aircraft *U-1, Soviet designation for

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

trainer *Multiple German U-boats named ''U-1'' * Oberursel U.I, an early German aircraft engine * HDMS U-1, a Danish submarine * SM U-1, an Austro-Hungarian submarine, lead ship of the U-1 class

Rail

Locomotives

* LNER Class U1, a 1924 British solitary loco * SR U1 class, a class of 2-6-0 locos

U-Bahn lines

* U1 (Berlin U-Bahn) * U1 (Frankfurt U-Bahn) * U1 (Hamburg U-Bahn) * U1 (Munich U-Bahn) * U1 (Nuremberg U-Bahn) * U1 (Vienna U-Bahn)

Other uses

*U1, unemployment figure released by Bureau of Labor Statistics *U(1), in abstract algebra, the

unitary group Unitary may refer to: Mathematics * Unitary divisor * Unitary element * Unitary group * Unitary matrix * Unitary morphism * Unitary operator * Unitary transformation * Unitary representation * Unitarity (physics) * ''E''-unitary inverse semi ...

of degree one * U1 spliceosomal RNA, a small nuclear RNA component of the spliceosome involved in pre-mRNA splicing * UNIONS 1 (U1), a star cluster of the Milky Way Galaxy