Melakarta is a collection of fundamental ragas (musical scales) in Carnatic music (South Indian classical music). Melakarta ragas are parent ragas (hence known as janaka ragas) from which other ragas may be generated. A melakarta raga is sometimes referred as mela, karta or sampurna as well.
In Hindustani music the thaat is equivalent of Melakarta. There are 10 thaats in Hindustani music, though the commonly accepted melakarta scheme has 72 ragas.
Read more about Melakarta: Rules For Melakarta, History, Determining The Melakarta, Melakarta Scale, Chakras, Table of Melakarta Ragas, Alternate Melakarta Scheme