Tonic Sol-fa is a music notation system that uses syllables to represent the notes of a scale. The syllables are do, re, mi, fa, sol, la, and ti, which correspond to the first seven notes of the major scale. This method simplifies sight-singing and helps musicians understand musical relationships more intuitively. Developed in the 19th century, Tonic Sol-fa is often used in choral settings and music education. It allows singers to learn melodies quickly without needing to read traditional sheet music. This approach has been influential in teaching music to children and in community singing groups.