All concepts
What is triad?
A three-note chord built by stacking two thirds — a , a third, and a fifth. Major and minor triads are the basic building blocks of harmony.
A triad is the smallest ordinary chord: take a root note, add the note a third above it, then the note a third above that (its fifth). Whether the two stacked thirds are major or minor decides the chord's flavour — a major third then a minor third gives a bright major triad; a minor third then a major third gives a darker minor triad. Nearly all chords in popular music are triads, or triads with extra notes piled on top.