Dominant Seventh Chord: A dominant seventh chord is a four-note chord consisting of a major triad with an added minor seventh interval. It has a strong sense of resolution.
Half-Diminished Chord (Minor 7th Flat 5): A half-diminished chord is also known as the "minor 7th flat 5" chord. It consists of a diminished triad with an added minor seventh interval.
Leading Tone: The leading tone refers to the seventh degree of any diatonic scale, which creates tension and leads strongly to the tonic note.