XX or xx may refer to: * 20 (number), 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'' * ''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 ** XX male syndrome, 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 sex chromosomes, in the XO sex-determination system * a

female An organism's sex is female ( symbol: ♀) if it produces the ovum (egg cell), the type of gamete (sex cell) that fuses with the male gamete (sperm cell) during sexual reproduction. A female has larger gametes than a male. Females and ...

, an organism producing ova gametes that fuse with the male gamete during sexual reproduction, typically having two X chromosomes in the XY and X0 sex determination systems

Music

* The xx, an English indie rock band * X_______X (band), an American no wave band

Albums

* '' Toto XX'', 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 * ''+ +'' (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, 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'', a group of twenty Belgian painters * Dos Equis or XX, a brand of Mexican beer * xx, to express

exponentiation In mathematics, exponentiation, denoted , is an operation (mathematics), operation involving two numbers: the ''base'', , and the ''exponent'' or ''power'', . When is a positive integer, exponentiation corresponds to repeated multiplication ...

in the initial version of the FORTRAN programming language