J, or j, is the tenth letter of the English alphabet. J may also refer to: *

Palatal approximant The voiced palatal approximant is a type of consonant used in many spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is ; the equivalent X-SAMPA symbol is j, and in the Americanist phonetic notation i ...

in the International Phonetic Alphabet * J, Cyrillic letter Je

Astronomy

* J, a provisional designation prefix for some objects discovered between May 1 and 15 of a year

Computing

* J (programming language), successor to APL * J# programming language for the Microsoft .NET Framework * J operator, a programming construct * J (operating system), an operating system for ICL's System 4 series of computers

Genetics and medicine

* Haplogroup J (mtDNA) *

Haplogroup J (Y-DNA) Haplogroup J-M304, also known as J,ISOGG] ''Y-DNA Haplogroup J and its Subclades - 2016'' (2 February 2016). is a human Y-chromosome DNA haplogroup. It is believed to have evolved in the Caucasus or Iran.' The clade spread from there during t ...

* ATC code J ''Antiinfectives for systemic use'', a section of the Anatomical Therapeutic Chemical Classification System

Mathematics

* J, symbol used to denote the Bessel function * ''j'', used as the symbol for the

imaginary unit The imaginary unit or unit imaginary number () is a mathematical constant that is a solution to the quadratic equation Although there is no real number with this property, can be used to extend the real numbers to what are called complex num ...

(

\sqrt

) in fields where ''i'' is used for a different purpose (such as electric current) * ''j'' and ''j²'' (or

\bar

) are also used for the complex cube

roots of unity In mathematics, a root of unity is any complex number that yields 1 when raised to some positive integer power . Roots of unity are used in many branches of mathematics, and are especially important in number theory, the theory of group char ...

* ''j'', a number with the property ''j'' ² = +1, used in the definition of the split-complex numbers * ''j'', the second imaginary unit of a

quaternion In mathematics, the quaternion number system extends the complex numbers. Quaternions were first described by the Irish mathematician William Rowan Hamilton in 1843 and applied to mechanics in three-dimensional space. The algebra of quater ...

* , an index variable in a matrix * The j-invariant, a modular function

Physics and chemistry

* J,

Joule The joule ( , or ; symbol: J) is the unit of energy in the International System of Units (SI). In terms of SI base units, one joule corresponds to one kilogram- metre squared per second squared One joule is equal to the amount of work d ...

, the SI unit of energy * J, the SI-recommended dimension symbol for

luminous intensity In photometry, luminous intensity is a measure of the wavelength-weighted power emitted by a light source in a particular direction per unit solid angle, based on the luminosity function, a standardized model of the sensitivity of the huma ...

, conventionally rendered in a sans-serif typeface * , current density * second moment of area * J, name given by Samuel C. C. Ting for the

J/ψ particle The (J/psi) meson is a subatomic particle, a flavor-neutral meson consisting of a charm quark and a charm antiquark. Mesons formed by a bound state of a charm quark and a charm anti-quark are generally known as " charmonium" or psions. Th ...

J-coupling In nuclear chemistry and nuclear physics, ''J''-couplings (also called spin-spin coupling or indirect dipole–dipole coupling) are mediated through chemical bonds connecting two spins. It is an indirect interaction between two nuclear spins tha ...

, indirect dipole-dipole coupling between two nuclear spins *

J (element) Iodine is a chemical element; it has Chemical symbol, symbol I and atomic number 53. The heaviest of the stable halogens, it exists at Standard temperature and pressure, standard conditions as a semi-lustrous, non-metallic solid that melts t ...

, atomic symbol of ''Jod'', German for iodine

Music

* J, stage name of Jang Ye-eun, a member of the K-Pop group

STAYC STAYC (; , acronym for Star to a Young Culture) is a South Korean girl group formed by High Up Entertainment. The group is composed of six members: Sumin, Park Si-eun (entertainer), Sieun, Isa, Seeun, Yoon, and J. Mainly produced by K-pop duo ...

J (Korean singer) Chung Jae-young (; born May 2, 1977), better known by the stage names J and J.ae (), is a Korean-American singer based in South Korea. She debuted in 1998 with the album, ''J: Gold''. Early life J was born Chung Jae-young on May 2, 1977. Her ...

, a Korean pop singer *

J (musician) , better known by his stage name J, is a Japanese musician, singer-songwriter and record producer. He is best known as bassist and co-founder of the rock band Luna Sea since 1986. After they disbanded in 2000 he focused on his solo career, for ...

, a Japanese rock musician * J., nickname of American White Zombie guitarist

Jay Yuenger Jay Noel Yuenger also known by the stage name "J.", is an American rock guitarist best known for his work with heavy metal band White Zombie. Career As a teenager, Yuenger's interests quickly progressed from pop to hard rock to hardcore pu ...

*J., stage name of German musician

Jaye Muller Jaye Muller (born Jens Müller) is a German musician and Internet entrepreneur who performed under the name J. in the 1990s, and later in a duo named "Muller and Patton" with American musician Ben Patton and since 2015 under the name "Count Jaye" ...

J Mascis Joseph Donald Mascis Jr. (born December 10, 1965), better known as J Mascis, is an American musician who is the singer, guitarist and main songwriter for the alternative rock band Dinosaur Jr. He has also released several albums as a solo artist a ...

, American singer and guitarist of Dinosaur Jr. *

J Records J Records was an American record label owned and operated by Bertelsmann Music Group until it was transferred to Sony Music Entertainment when they acquired all of BMG's record labels in late 2008 at the end of their merger. It was distribut ...

, a record label

Albums

* ''J'' (Jaehyun album), album by South Korean singer Jaehyun

Songs

* "J", song by Reggie and the Full Effect from the album '' Last Stop: Crappy Town'' * "J", song by Mindless Self Indulgence from the album '' Frankenstein Girls Will Seem Strangely Sexy''

Film and television

* Agent J, a character in the ''Men in Black'' films portrayed by Will Smith * J, an antagonist in '' Bobobo'' * '' Kamen Rider J'', a Japanese movie *J, the production code for the 1964 ''Doctor Who'' serial '' Planet of Giants'' * Serial Designation "J", one of the antagonists from the web series '' Murder Drones'' (2021-2024)

Writers

* J (sometimes given as I), pen name of the Danish novelist Cornelia von Levetzow (1836–1921)

Transportation

* J (Los Angeles Railway) * J (New York City Subway service) * J Church (San Francisco Muni) * J Line (Los Angeles Metro) * NZR J Class, a 4-8-2 type class of steam locomotive used by New Zealand Railways * Transilien Line J, a line of the Paris transport network * JRW kinki-J

, the official West Japan Railway Company service symbol for the Bantan Line * Saviem J, also known as the Renault J, a range of medium-duty trucks * "The J", a nickname for the Elgin, Joliet and Eastern Railway, a former railroad

Other uses

* J, slang for joint (cannabis) * J, slang for Air Jordan shoes * J, slang for a jump shot in basketball * J band (disambiguation) * J (psychedelic), an entactogenic drug * Elgin, Joliet and Eastern Railway, a Chicago railway sometimes referred to as "The J" * J, the international license plate code for Japan * J, the

Canadian postal code A Canadian postal code () is a six-character string that forms part of a postal address in Canada. Like British, Irish, Dutch, and Argentinian postcodes, Canada's postal codes are alphanumeric. They are in the format ''A1A 1A1'', where '' ...

for the western and northern regions of Quebec * J, German mint mark for the city of Hamburg * J abbreviation for Jahwist, one of the hypothesized major authors of the Torah * J, an abbreviated title of a High Court judge (in Law Reports, etc.), e.g. Bloggs J * '' J. The Jewish News of Northern California'', a weekly newspaper serving the Jewish community in Northern California * J, the narrator of Jerome K. Jerome's novel '' Three Men in a Boat'' * J., Jezper Söderlund, the trance artist * Lamborghini Aventador J, a 2012 Lamborghini supercar * ''J'' (novel), a 2014 novel by Howard Jacobson * ''ʲ'', the symbol for Palatalization in the IPA * Juliet, sometimes used as the unofficial military time zone code for local time * '' "J" Is for Judgment'', the tenth novel in Sue Grafton's "Alphabet mystery" series, published in 1993 * Guy Big J, range of trucks produced by Guy Motors of England between 1964 and 1978 * code for

academic journal An academic journal (or scholarly journal or scientific journal) is a periodical publication in which Scholarly method, scholarship relating to a particular academic discipline is published. They serve as permanent and transparent forums for the ...

in the reference section of an academic work