The term BACKBONE OF INDIAN CLASSICAL MUSIC is represented by the crossword solution RAGA, which is a four letter word. Raga is an ancient Indian musical form that has been used for centuries to create melodic compositions. It is based on a set of rules and guidelines that govern the structure of the music, including the use of specific notes, scales, and rhythms. Raga is considered to be the backbone of Indian classical music, as it provides the foundation for many of the traditional pieces.