In music, a minor chord is a combination of three different notes. For example, when using a piano, and you want to play the C minor chord (Cm, as minor chords are always denoted with a small 'm'), you must play C, followed by Eb, followed by G.
Minor Chord Media
A minor triad has a minor third (m3) on the bottom, a major third (M3) on top, and a perfect fifth (P5) between the outer notes.