These major or minor chords contain three different notes: a root (eg the E note in E), a 3rd interval up from the root (eg the G# note in E) and a 5th interval up from the root (eg the B note in E).

This interval is called a fifth. Try to play this interval on a keyboard or piano. A chord is a group of notes - usually three or more - which are stacked vertically. They are played together and ...