The term Muslim world (also known as the Ummah or Islamosphere) has several meanings. In a religious sense, it refers to those who adhere to the teachings of Islam, referred to as Muslims. In a cultural sense, it refers to Islamic civilization, inclusive of non-Muslims living in that civilization. In a modern geopolitical sense, the term usually refers collectively to Muslim-majority countries, states, districts, or towns.

Islam emphasizes unity and defense of fellow Muslims, although many schools and branches (see Shi'a–Sunni relations, for example) exist. In the past both Pan-Islamism and nationalist currents have influenced the status of the Muslim world.

As of 2009, over 1.6 billion or about 23% of the world population are Muslims. Of these, around 62% live in Asia-Pacific, 20% in the Middle East-North Africa, 15% in Sub-Saharan Africa, around 3% in Europe and 0.3% in the Americas.

Muslim history involves the history of the Islamic faith as a religion and as a social institution. The history of Islam began in Arabia with the Islamic prophet Muhammad's first recitations of the Quran in the 7th century. Under the Rashidun and Umayyads, the Caliphate grew rapidly geographically expansion of Muslim power well beyond the Arabian Peninsula in the form of a vast Muslim Empire with an area of influence that stretched from northwest India, across Central Asia, the Middle East, North Africa, southern Italy, and the Iberian Peninsula, to the Pyrenees.

Katheryn Elizabeth Hudson (born October 25, 1984), known by her stage name Katy Perry, is an American singer, songwriter and actress. Perry grew up with gospel music, and during her first year of high school she pursued a music career as Katy Hudson, releasing her first studio album called Katy Hudson which failed to chart. She recorded a solo album later, which was never released. After signing with Capitol Music Group in 2007, her fourth record label in seven years, she adopted the stage name Katy Perry.

She first gained recognition with the release of her first mainstream album, One of the Boys in 2008, which spawned three Billboard Hot 100 top-ten songs—"I Kissed A Girl", "Hot n Cold" and "Waking Up In Vegas". Perry supported the album with her Hello Katy Tour. In 2010, her third studio album, Teenage Dream (2010), which topped the Billboard 200 chart, and spawned five number one singles—"California Gurls", "Teenage Dream", "Firework", "E.T." and "Last Friday Night (T.G.I.F.)"—Teenage Dream was the only album (after Michael Jackson's Bad)—to do so, and the first female in history to achieve this milestone. She embarked on the California Dreams Tour, which grossed nearly $60 million worldwide. Perry re-released the album under the name of Teenage Dream: The Complete Confection on March 26, 2012, and the re-release has already spawned the number-one single "Part of Me".

Dark horse is a term used to describe a little-known person or thing that emerges to prominence, especially in a competition of some sort or a contestant that seems unlikely to succeed.

The term began as horse racing parlance. A dark horse is a race horse that is not known to gamblers and thus is difficult to place betting odds on.

The earliest-known use of the phrase is in Benjamin Disraeli's novel The Young Duke (1831). Disraeli's protagonist, the Duke of St. James, attends a horse race with a surprise finish: "A dark horse which had never been thought of, and which the careless St. James had never even observed in the list, rushed past the grandstand in sweeping triumph."

The term has been used politically in such countries as Peru, Philippines and United States.

Politically, the term reached America in the nineteenth century when it was first applied to James K. Polk, a relatively unknown Tennessee Democrat who won the Democratic Party's 1844 presidential nomination over a host of better-known candidates. Polk won the nomination on the ninth ballot, and went on to win the presidential election.