A chord is simply three or more notes sounded together. The lowest note gives the chord its name — that is the root — and the notes above it decide whether it sounds bright, sad, or restless.

The most common chord of all is the triad: a root, a third, and a fifth. C major is C, E and G. Everything else in this glossary is a triad with something added or swapped.

Major and minor differ by a single note. A major chord uses a major third — four semitones above the root. A minor chord lowers that third by one semitone, and that one small change is what makes a minor chord sound darker.

In practice: C is C, E, G. C minor is C, E flat, G. Same shape on the page, completely different mood.

Add one more note on top of a triad and you get a seventh chord. A plain 7 — as in G7 or D7 — adds a note that wants to move, which is why it usually appears right before the song returns home.

A maj7 is softer and more open, the sound of a slow ballad. A minor 7 is mellow and a little wistful. The glossary shows the shapes for all of them.

The key of a song is its home note — the chord that feels finished. If a song is in G, then G is where it resolves, and the other chords are chosen to pull you back there.

Every song page in the songbook lists its key. Knowing it tells you which chords to expect and where the song is heading.

Players often talk about chords by number rather than letter, because the numbers stay the same in every key. In any major key, the seven chords are: I, ii, iii, IV, V, vi, vii.

Capital letters mean major, small letters mean minor. So in the key of G, I is G, IV is C, V is D, and vi is Em. Move the same song to the key of C and the numbers do not change — only the letters do.

I - IV - V is the oldest progression in folk, country and gospel. In G that is G - C - D, and you will find it in song after song here.

I - V - vi - IV is the modern workhorse, heard in countless ballads and pop songs. vi - IV - I - V is the same loop started in a different place.

The twelve-bar blues follows I - I - I - I - IV - IV - I - I - V - IV - I - V, one bar each. Once you hear it, you will spot it everywhere.

When you open a song, look at the key and the chord list first. The numbers behind those chords tell you which ones carry the weight and which ones simply pass through.

If a progression feels hard, strip it back to the root notes only, then add the rest of each chord back one at a time. The shape of the song stays the same even when the voicings get simpler.