What is Carnatic Music?
"Carnatic music or Karnāṭaka Saṃgīta is a system of music commonly associated with the southern part of the Indian subcontinent, with its area roughly confined to four modern states of India: Andhra Pradesh, Karnataka, Kerala, and Tamil Nadu. It is one of two main sub-genres of Indian classical music that evolved from ancient Hindu traditions; the other sub-genre being Hindustani music, which emerged as a distinct form because of Persian and Islamic influences in North India. The main emphasis in Carnatic music is on vocal music; most compositions are written to be sung, and even when played on instruments, they are meant to be performed in gāyaki (singing) style." Carnatic Music (Wikipedia)
See also Karnatak music (Grove Dictionary of Music and Musicians) (UIUC affiliates only)