A major interval is a specific distance between two notes in music that creates a bright and happy sound. It is defined by the number of half steps between the notes. For example, the interval from C to E is a major third, consisting of four half steps. In Western music, major intervals are essential for constructing major scales and chords. They contribute to the overall harmony and mood of a piece. Understanding major intervals helps musicians create melodies and harmonies that evoke positive emotions in listeners.