The Jonas Brothers are an American pop rock band composed of three brothers: Kevin, Joe, and Nick Jonas. The band was formed in 2005 and released their debut album in 2006. They have since released five studio albums and have become one of the most successful musical acts of the 21st century. The term 'Jonas Brothers, e.g.' can be used to refer to any TRIO of siblings who form a band, and the answer to the crossword clue is 'TRIO'.