<p>In this episode I respond to one of the community-requested topics ("Music Theory") and try to explain what <strong>seventh chords</strong> are and why they are used. Below are some of the terms that I use in the course of the discussion.</p> 

<ul>
<li><strong>Interval</strong>: The distance between two pitches (sounded either consecutively or simultaneously)</li>
<li><strong>Consonance</strong>: Relatively stable sound between two or more pitches</li>
<li><strong>Dissonance</strong>: Relatively unstable sound between two or more pitches. Dissonance often needs a &quot;resolution&quot; to consonance</li>
<li><strong>Chord</strong>: three or more notes sounded together </li>
<li><strong>Chord progression</strong>: a succession of chords </li>
<li><strong>Triad</strong>: a chord with 3 pitches, the adjacent pitches separated by the interval of the 3rd.</li>
<li><strong>Seventh chord</strong>: a chord with 4 pitches, the adjacent pitches separated by the interval of the 3rd.</li>
<li><strong>Tonality</strong>: harmonic system that governs the use of major and minor keys</li>
<li><strong>Tonic</strong>: the central tone of a piece of music</li>
<li><strong>Mode</strong>: major or minor [e.g. Symphony no. 5 in C minor]</li>
<li><strong>Modulation</strong>: the process of changing keys within a piece of music </li>
<li><strong>Scale</strong>: Ascending or descending series of notes that define a key or tonality, with a specific arrangements of half-steps and whole-steps. Major and Minor scales are most common in Western music</li>
</ul>


<p>Free public-domain music reference book: <em>Music Notation and Terminology</em> by Karl Wilson Gehrkens: <a href="https://www.gutenberg.org/ebooks/19499">https://www.gutenberg.org/ebooks/19499</a> (see ch. 18)</p>

<p>Free Online Music Dictionary: <a href="https://dictionary.onmusic.org">https://dictionary.onmusic.org</a>/</p>