1. A British rock band. 2. A U.S. psychedelic rock band. 3. A K-pop girl group. (other tags include ė ģøė³“ģ°) 1. Rainbow was a British rock band formed by Deep Purple founder and former guitarist Ritchie Blackmore in 1975. In addition to Blackmore, the band originally consisted of former Elf lead singer Ronnie James Dio, bassist Craig Gruber, drummer Gary Driscoll, and keyboardist Micky Lee Soule. Over the years, Rainbow went through many lineup changes. Read more on Last.fm