"Mensa" is not actually an abbreviation. It is the Latin word for table. Mensa International is a club for people with high intelligent quotients (IQs).
Mensa International adopted the name because it strives to be a "round-table society where race, color, creed, national origin, age, politics, education or social background are irrelevant." Mensa welcomes anyone who has an IQ in the top 2 percent of the population to become a member, and it takes no stance on issues of faith or politics. It was founded in 1946 by Roland Berrill, a barrister, and Dr. Lance Ware, a scientist and lawyer. The club's membership exceeds 110,000 as of 2014.