An augmented triad is made up of two major 3rd intervals. In Tertian harmony chords are built by stacking 3rds, there are two types of 3rds, major and minor. Major is the larger of the two and therefore when stacking two major 3rds the chord that results is called augmented, the distance has been expanded or “augmented”. An Augmented triad spans a greater distance than Major, Minor or Diminished.