U.s. Open

Open is applied to "open" United States national championships in a particular sport, in which anybody, amateur or professional, American or non-American may compete. Open (golf), golf tournament of the United States Golf Association
US Open (tennis), fourth event of the Grand Slam tournaments
U.S.Open Cup, soccer tournament held between American soccer clubs from the MLS and the minor leagues
U.S. Open (taekwondo) Taekwondo tournament of the United States Taekwondo governing body
U.S.Open (USACO) United States Computing Olympiad proctored competition conducted during the month of April
U.S.