The root of chord is the note upon which that chord is built or centered. This feeling of centeredness is readily perceivable aurally, and is perhaps the pitch that would be most commonly sung if a chord was played and people were asked to sing a note in said chord. When the chord is uninverted, or in root position, this is the bottom note of the chord.

Conventionally the name of the note which is the root is used to denote the chord, thus a major chord built on C is a C Major chord. The analysis and theory of tonal music usually treats the roots as the defining feature of chords and much information can be gained from a progression of roots even if chord types are unknown. Also, if the key is known then the chord forms are known for each root.

Often the root is not actually the lowest pitch being played in a chord, in which case the chord is inverted.