Here is a definition for a chord: A chord in music is any harmonic set of two to three or more notes that is heard as if sounding simultaneously.
So, one note is not a chord, but two notes can be when the listener hears them together.
There are four different kinds of chords:
- Major
- Minor
- Diminished
- Augmented
In popular music, rock, country, folk, blues.. we hear mostly major and minor chords. When you listen to Classical and Jazz then diminished and augmented chords come into play more often. (This is a generalization of the styles and there are exceptions to all of these comments.)
