A minor third is a musical interval that spans three half steps, or semitones, between two notes. For example, if you start on the note C and move up to E♭, you have created a minor third. This interval is often associated with a sad or melancholic sound in music. In Western music, minor thirds are commonly found in chords and melodies. They are essential in forming minor chords, which consist of a root note, a minor third, and a perfect fifth. Understanding minor thirds helps musicians create emotional depth in their compositions.