The acronym for the US professional soccer organization is USSF. It stands for the United States Soccer Federation. USSF has an affiliation with the international governing body for soccer: FIFA.
USSF was founded in 1913 and was originally called the United States Football Association. In 1930, the United States was one of 13 countries at the first FIFA World Cup, held in Uruguay. It became the U.S. Soccer Federation in 1974. USSF hosted the World Cup in 1994, which was the first time it was held in the the United States. Five years later, it hosted the Women's World Cup in the United States for the first time.