XX or xx may refer to: *

20 (number) 20 (twenty; Roman numeral XX) is the natural number following 19 and preceding 21. A group of twenty units may also be referred to as a score. In mathematics *20 is a pronic number. *20 is a tetrahedral number as 1, 4, 10, 20. *20 is the ba ...

, Roman numeral XX

Film and TV

* ''XX'' (film), a 2017 anthology horror film * "XX", an episode of ''CSI: Crime Scene Investigation'' (season 4) *XX, the production code for the 1969 ''Doctor Who'' serial ''

The Seeds of Death ''The Seeds of Death'' is the fifth serial of the sixth season of the British science fiction television series ''Doctor Who''. Written by Brian Hayles and an uncredited Terrance Dicks and directed by Michael Ferguson, it originally aired in ...

'' * ''XX'' (web series), a 2020 South Korean web series * XX (organization), a fictional organisation in the comic and game ''XIII''

Genetics

*XX sex chromosomes, in the

XY sex-determination system The XY sex-determination system is a sex-determination system used to classify many mammals, including humans, some insects (''Drosophila''), some snakes, some fish (guppies), and some plants (''Ginkgo'' tree). In this system, the sex of an indi ...

XX male syndrome XX male syndrome, also known as de la Chapelle syndrome, is a rare congenital intersex condition in which an individual with a 46, XX karyotype (otherwise associated with females) has phenotypically male characteristics that can vary among case ...

, also known as de la Chapelle syndrome, a rare congenital intersex condition resulting in a phenotypical male with two X chromosomes ** XX gonadal dysgenesis, a type of female hypogonadism resulting in non-functioning ovaries * XX chromosome, in the

XO sex-determination system The XO sex-determination system (sometimes X0 sex-determination system) is a system that some species of insects, arachnids, and mammals use to determine the sex of offspring. In this system, there is only one sex chromosome, referred to as X. Male ...

Music

The xx The xx are an English indie rock band from Wandsworth, London, formed in 2005. The band consists of Romy Madley Croft (guitar, vocals), Oliver Sim (bass guitar, vocals), Jamie Smith, also known as Jamie xx (beats, MPC, record production), a ...

, a British indie band * X_______X (band), a Cleveland no wave band

Albums

* ''

Toto XX ''Toto XX: 1977-1997'' is a compilation album by Toto to celebrate their 20th anniversary. The album features rare original demos, outtakes, previously unreleased recordings and live tracks from the band's 20-year career. The first single releas ...

'', a 1998 album by Toto * ''XX'' (Mushroomhead album), 2001 * ''xx'' (The xx album), 2009 * ''XX'' (Great Big Sea album), 2012 * '' XX – Two Decades of Love Metal'', a 2012 compilation album by HIM * ''XX'' (O.A.R. album), 2016 * ''XX'' (Mino album), 2018 * ''XX'', a 2018 album by

Note-oriety Note-oriety is an upper voices a cappella singing group at James Madison University in the United States, founded in 1998 by Kelly Myer and Bonnie Estes. The group sings in and around Harrisonburg, Virginia, tours the east coast and other parts ...

* ''+ +'' (EP), a 2018 EP, repackaged as '' X' in 2019, by Loona

Songs

* "xx", a song by Hayley Kiyoko from '' Expectations'' * "XX", a song by Feid from '' Ferxxo (Vol 1: M.O.R)''

Organisations

XX Bomber Command The XX Bomber Command was a United States Army Air Forces bomber formation. Its last assignment was with Twentieth Air Force, based on Okinawa. It was inactivated on 16 July 1945. History The idea of basing Boeing B-29 Superfortresses in C ...

, an inactive United States Air Force unit * XX Corps (disambiguation) * '' Legio XX Valeria Victrix'' or Legion XX, a legion of the Roman Empire

Other uses

* ''XX'' (novel), a 2020 novel by Rian Hughes * XX System or Double-Cross System, a British deception operation in the Second World War * ''

Les XX ''Les XX'' ( French; "''Les Vingt''"; ; ) was a group of twenty Belgian painters, designers and sculptors, formed in 1883 by the Brussels lawyer, publisher, and entrepreneur Octave Maus. For ten years, they held an annual exhibition of their art ...

'', a group of twenty Belgian painters *

Dos Equis DOS is shorthand for the MS-DOS and IBM PC DOS family of operating systems. DOS may also refer to: Computing * Data over signalling (DoS), multiplexing data onto a signalling channel * Denial-of-service attack (DoS), an attack on a communicatio ...

or XX, a brand of Mexican beer * xx, to express

exponentiation Exponentiation is a mathematical operation, written as , involving two numbers, the '' base'' and the ''exponent'' or ''power'' , and pronounced as " (raised) to the (power of) ". When is a positive integer, exponentiation corresponds to re ...

in the initial version of the FORTRAN programming language