Number sign is a name for the symbol #, which is used for a variety of purposes including, in some countries, the designation of a number (for example, "#1" stands for "number one"). The symbol is defined in Unicode as U+0023 # number sign (HTML: #); it is also present in ASCII with the same value.

In Commonwealth English, the symbol is usually called the hash and the corresponding telephone key is called the hash key. In American English, the symbol is usually called the pound sign^{[citation needed]} (outside the US, this term often describes instead the British currency symbol "£") and the telephone key is called the pound key. In Canadian English, this key is most frequently called the pound key but also in some circumstances the number sign key.

In many parts of the world, including most of the Commonwealth nations, Russia, and most of Europe, number sign refers to the numero sign (№).

The symbol is easily confused with the musical symbol called sharp (♯). In both symbols, there are two pairs of parallel lines. The key difference is that the number sign has true horizontal strokes while the sharp sign has two slanted parallel lines which must rise from left to right, in order to avoid being confused with the musical staff lines. Both signs may have true vertical lines; however, they are compulsory in the sharp sign, but optional in the number sign (#) depending on typeface or handwriting style. Thus, only the number sign may have an italic appearance.

Jessica Ellen Cornish (born 27 March 1988), better known by her stage name Jessie J, is an English singer and songwriter. Born and raised in London, she studied at the BRIT School before signing with Gut Records and striking a songwriting deal with Sony/ATV Music Publishing where she wrote for artists such as Chris Brown and Miley Cyrus.

Signed with Universal, Jessie J came to prominence following the release of her debut single "Do It Like a Dude" which peaked at number two on the UK Singles Charts. After scoring her first number one in the United Kingdom, France, Ireland and New Zealand with the song "Price Tag", she released her debut album Who You Are (2011) which charted at number two in the UK. Other releases from the album include "Nobody's Perfect", "Who's Laughing Now" and "Who You Are" which charted within the top 20 in the UK but the release of fifth single "Domino" spawned international chart success, peaking at number 6 on the Billboard Hot 100 in the US, and becoming her second UK number one. Aside from her musical career, Jessie J is currently a coach and mentor on television show The Voice UK.

Sara Beth Bareilles ( /bəˈrɛlɪs/ bə-REL-is; born December 7, 1979) is an American singer-songwriter and pianist. She achieved mainstream success in 2007 with the hit single "Love Song", which brought her into the number one spot on the Billboard Pop 100 chart. She has sold over 1 million records in the United States alone and has been nominated for a Grammy Award three times. In the third season of NBC's The Sing-Off, Bareilles was a celebrity judge alongside Ben Folds and Shawn Stockman of Boyz II Men. In February of 2012, VH1 placed Bareilles in the #80 spot of the Top 100 Greatest Women in Music.

Bareilles was born and raised in Eureka, California, the youngest of three daughters of Bonnie Halvorsen (née Capellas), a funeral home worker, and Paul Bareilles, an insurance adjuster. She is of Italian, German, Portuguese, and French descent (she speaks Italian and lived in Italy for a year). Bareilles was raised Catholic and participated in the high school choir, Limited Edition, and local community theater musical productions, including her high school's production of Little Shop of Horrors as Audrey.

Alicia Augello Cook (born January 25, 1981), better known by her stage name Alicia Keys, is an American R&B singer-songwriter, record producer, and actress. Keys was raised by a single mother in the Hell's Kitchen area of Manhattan in New York City. At age seven, Keys began playing the piano. She attended Professional Performing Arts School and graduated at 16 as valedictorian. Keys released her debut album with J Records, having had previous record deals first with Columbia and then Arista Records.

Keys' debut album, Songs in A Minor, was a commercial success, selling over 12 million copies worldwide. She became the best-selling new artist and best-selling R&B artist of 2001. The album earned Keys five Grammy Awards in 2002, including Best New Artist and Song of the Year for "Fallin'". Her second studio album, The Diary of Alicia Keys, was released in 2003 and was also another success worldwide, selling eight million copies. The album garnered her an additional four Grammy Awards in 2005. Later that year, she released her first live album, Unplugged, which debuted at number one in the United States. She became the first female to have an MTV Unplugged album to debut at number one and the highest since Nirvana in 1994.

Onika Tanya Maraj (born December 8, 1982), known by her stage name Nicki Minaj ( /mɪˈnɑːʒ/), is a Trinidadian-born American rapper and singer-songwriter. She was born in Saint James, Trinidad and Tobago and when she was 5 years of age she moved to the New York City borough of Queens, where she grew up.

After releasing three mixtapes between 2007 and 2009 and being signed to Young Money Entertainment in August 2009, Minaj released her debut album, Pink Friday, in November 2010. It quickly became a commercial success, peaking at number one on the U.S. Billboard 200 and being certified Platinum by the Recording Industry Association of America (RIAA) a month after its release. She became the first female solo artist to have seven singles on the Billboard Hot 100 at the same time. Her second single, "Your Love", reached number 1 on the Billboard Hot Rap Songs chart, making Minaj the first female artist to top the chart unaccompanied since 2002. She also became the first female artist to be included on MTV's Annual Hottest MC List. Minaj was named the 2011 Rising Star by Billboard. Her second studio album, Pink Friday: Roman Reloaded was released on April 3, 2012.