UU or uu may refer to: Businesses United Utilities (LSE stock symbol UU) Air Austral (IATA airline code UU) Language "uu", an old way of spelling the letter "w" in certain Germanic languages, including Old English The letter combination of uu Science and technology UUNET, Internet Service Provider commonly referred to as 'UU' Unique users, may be counted as part of web analytics in determining the popularity of a website UMTS air interface or "Uu interface", which links User Equipment to the UMTS Terrestrial Radio Access Network Unix-to-Unix, as in uuencode, a data transport encoding .uu, a compressed archive file extension, associated with uuencode Universities Ulster University in Northern Ireland University of Utah in Salt Lake City, Utah, United States Uppsala University in Sweden Utrecht University in the Netherlands Uttaranchal University in Uttarakhand, India Other uses Union of Utrecht (Old Catholic), a federation of Old Catholic churches Unitarian Universalism, a theologically liberal religion characterized by its support for a "free and responsible search for truth and meaning." Unseen University, in the fictional Discworld novels of Terry Pratchett UU, the production code for the 1968 Doctor Who serial The Mind Robber U'u a war club from Marquesas Islands Undead Unluck a shorthand for the manga by Yoshifumi Tozuka. See also VV (disambiguation) W (disambiguation) 2U (disambiguation) U2 (disambiguation)