Chord
Two or more notes played together.
Triad
A three-note chord built on the 1st, 3rd, and 5th of a scale.
Cadence
A two chord progression that ends a phrase or section or song.
Perfect cadence
Chords V–I, sounds finished.
Imperfect cadence
Ends on chord V, sounds unfinished.
Major
Tonality/chord that sounds bright or happy.
Minor
Tonality/chord that sounds dark or sad.
Drone
A sustained note or notes throughout a piece.
Pedal note
A held or repeated note in the bass while chords/harmonies change above it.
(Shorter than a drone)
Dissonance
Clashing notes/chord that create tension.