There are at least four artists with this name.
1. AOA (an acronym for Ace of Angels) is a South Korean idol girl group signed under FNC Entertainment. AOA debuted as an eight-member band that consists of Choa, Jimin, Yuna, Youkyung, Chanmi, Hyejeong, Seolhyun, and Mina. Currently, AOA is promoting as a seven-member idol group without Youkyung, who is only a part of AOA Black. The group officially debuted with their first single album Angels' Story, released on July 30th, 2012.
2. Working the same way that a DJ works and works on a dancefloor, AOA is an improvised jam unit. Based on the core members of Boredoms bassist Hilah, Bordoms drummer/session percussionist E-Da, Tribal Circus' Miya, Soft's drummer/electronics operator Shinkichi, DJ Tateyamars (programming/sound FX) and session guitarists Bravo Komatsu (Pizzicato 5).
3. AOA (All Out Attack) Anarcho punk from Edinburgh Scotland.
4. AOA is also a c-pop group with at least one album out named "同名专辑".