XX

Look up XX, xx, or x_x in Wiktionary, the free dictionary.

XX or xx most often refers to:

• 20 (number), Roman numeral XX

XX or xx may also refer to:

Genetics

• An organism with two X chromosomes, in the XY sex-determination system (of humans, as well as some other animals and some plants) and the XO sex-determination system (of some animals):
  • Usually female, producing ova gametes that fuse with the male gamete during sexual reproduction
  • XX male syndrome (AKA de la Chapelle syndrome), a rare congenital intersex condition

Arts and media

Military

• XX System or Double-Cross System, a British deception operation in the Second World War
• XX Bomber Command, an inactive US Air Force unit
• XX Corps (disambiguation)
• Legio XX Valeria Victrix, a legion of the Roman Empire

Computing

• xx, to express exponentiation in the initial version of the FORTRAN programming language
• .xx ("dot ex ex"), a placeholder for an Internet country code top-level domain

Other uses

• Dos Equis or Siglo XX, a brand of Mexican beer

See also

• XX gonadal dysgenesis, a type of female hypogonadism resulting in non-functioning ovaries
• All pages with titles containing XX
• All pages with titles containing ex ex
  • Ex-ex-gay, a social movement
  • United States Exploring Expedition of 1838–1842 to the Pacific Ocean and surrounding lands
  • Ex Ex Lovers, a 2025 Philippine romantic comedy film
• 20 (disambiguation)
• Double Cross (disambiguation)
• X (disambiguation)
• XXX (disambiguation)
• XXXX (disambiguation)

This disambiguation page lists articles associated with the title XX.
If an internal link incorrectly led you here, you may wish to change the link to point directly to the intended article.