<human>:  Why is the Indian classical music form called a raga?
<bot>: The word raga is a Sanskrit word meaning color or shade. The word is used to describe the mood or character of a piece of music. Raga is a very important part of Indian classical music. The raga is the foundation of a song, and it determines the key, the tempo, and the melody. A raga is usually characterized by a specific combination of notes, and it is often represented by a diagram.