The "term" has existed likely as long as there has been written music...LOL
Yes, I was just saying that even though I didn't confirm the definition prior to now, it's something I've always done and assume everyone has. 3 note, 4 note, 2 note, any form of partial chords are just that, right? What sparked my initial comment was another member saying they were spending a bunch of time on Triads, so I thought perhaps I was missing something, but it is what I thought it was. I'm sure I learned it in my youth, and when it came up, I thought I knew what it meant, but thought there might be more too it.
Chord theory refresher? Maybe this will be helpful...maybe you already know it. If you already know it, my apologies. But maybe it will be helpful to someone else. I wish someone would have explained it to me this way.
Common Triads are constructed by playing every second note of the scale....twice starting at the root.
Looking at scale steps, the root is the first note of the scale/chord (the I). The
second note of the chord is
the third note of the scale. Every second note. If it is a major scale
"the third" is two full steps above the root and is said to be a
major third. If it is a minor scale, the third is 1.5 steps above the root and is said to be a
minor third. It is the third of the chord that distinguishes minor chords from major chords.
The third note of the chord is the fifth note of the scale and finishes off the triad. The formula for a major triad is I, III, V. The formula for a minor triad is I, flat III and V. The Roman Numerals refer to the steps of the scale used in the chord.
If you continue the pattern and add the note two steps above the fifth, you have added the VII note of the scale and constructed a 7th chord. If the VII note is one step below the root it is a
Minor 7 chord. If it is 1/2 step below the root it is a
Major 7 chord.
You can also add other notes of the scale like the second step (II) of the scale (an octave higher) to make a 9th chord, the fourth step to construct an 11th chord, the 6th note of the scale to construct a 13th chord etc. As you may have noticed, whatever step you add, is numbered 7 higher than the actual interval because it is played at the octave. These are called extended chords.
A lot of players will use chords without the third to remove the minor/major distinction which allows more versatility. If you just play the I and V of the scale (no III), it is a power chord. But you can also leave out the third and add a 7th 9th etc. to make "extended triads" (three notes).
Edit: This process of taking every second note is called harmonizing the scale and is used to construct the chords of each key. If you start on the root (I) it is the first chord of the key, start on the second note of the scale and it forms the II chord (second chord of the key).