Summary
- the tonic is the first note of a scale, the root is the first note of a chord
That’s the short answer. However, a lot of people get confused when it comes to scales and chords, even when they think they know what they are. After all, isn’t the C major triad just the 1st, 3rd and 5th notes of the C major scale, so the tonic and the root are the same: C?
Here’s the longer answer:
Scales
Consider the opening of Harold Arlen’s Over the Rainbow
:

Before we get to the end of the second phrase, we’ve covered all the white notes from C to C:

which, as some of you will know, is the C major scale. That’s the real meaning of a scale:
- a scale is a set of notes a melody is based on
Now look at melody on the page again. It’s lots of single notes, one after the other:

For that reason, we say that melody is the horizontal aspect of music.
- melody = horizontal = scale
Now, if you’re playing on the white notes, why is C the tonic, and not D or E, etc.? Let’s look at the end of the tune:

If you play Over the Rainbow
on the white notes, it finishes on C. In fact, most tunes played on the white notes finish on C:



It’s as if C exerts a gravitational pull on the melody. For that reason, I prefer to call the tonic the home note
of a scale rather than the first note. It’s the note that a tune comes home to. So:
- the tonic is the
home note
of a scale
and
- melody = horizontal = scale = tonic
Chords
Now chords. First of all, what is a chord?
- a chord is more than one note happening at once
It doesn’t have to be a triad or a seventh, it really is just any bunch of notes happening at once.
Here’s the opening of Over the Rainbow
with chords:

Now look at any chord in Over the Rainbow. It’s always a bunch of notes on top of each other:

For that reason, we say that harmony is the vertical aspect of music.
- harmony = vertical = chord
Once again, I prefer to use the phrase home note
when describing a root, because a root isn’t always the first note of a chord. For instance, it doesn’t matter how you arrange C, E and G, they always make up a C major chord:

So:
- the root is the
home
note of a chord
and
- harmony = vertical = chord = root
Horizontal vs vertical
So, why is this all so important? Look at the opening of Over the Rainbow
with chords again:

The roots of the chords are C, A, E, C, F, B, C. However, all of the chords use white notes only, which is the C major scale, so the tonic is always C.
- the root can change while the tonic stays the same
For that reason:
- always keep horizontal and vertical separate in your mind
If you say C major
, you need to know whether you’re referring to the C major scale (horizontal) or a C major chord (vertical), as they don’t always go together.
- melody = horizontal = scale = tonic
- harmony = vertical = chord = root
Carve it in stone.