A chord consisting of a major third and a perfect fifth. For example, a D major chord (D) contains D, F#, and A.

A chord with a major 3rd interval between the root and the 3rd.

A triad composed of a root, major third, and perfect fifth.

Generally speaking, a major chord is any chord which has a major third above its root, as opposed to a minor chord which has a minor third. More specifically, it is the three-note chord made up of a major third and perfect fifth above the root—if the root of the chord is C, the chord will consist of the notes C, E and G. This is also known as a major triad.