What is the significance of the triad in music theory and how does it contribute to the harmonic structure of a piece?

The triad is a fundamental building block in Music Theory, consisting of three notes stacked on top of each other. It is significant because it forms the basis of harmony in music. Triads create a sense of stability and tension, which contributes to the overall harmonic structure of a piece by providing a foundation for chord progressions and creating a sense of resolution or movement within the music.