Ken Bloom wrote:
Two notes define an interval. Three notes define a chord. Two notes IN CONTEXT suggest a chord. For instance, if you have D and F# together they could suggest a D chord, a B minor chord an E9, a G major seven chord etc. and these are just the obvious ones. This is a very minor point of sematics but I was an English major and have always found the language of music to be very precise. Just my 2p.
There are two points here that need a bit of elaboration, at least to illustrate how some of this stuff works in my crazy little compositional/improvisational world FWIW:
1.) CONTEXT -- this is a big one really. Often, my "context" may be a virtual (implied but not sounded) triadic reference structure, over which I may be playing some two-note dyads. I know this sounds deep and very conceptual, but that's the way I seem to work, at least part of the time. So it doesn't matter to me what a dictionary says -- the dyad is simply doing something harmonic to my reference structure.
2.) SUGGEST -- the power of suggestion!! Dyads may suggest many different possibilities. One that comes to mind right away for me is looking at them as, say, an upper part of a polychord structure, where you might have a lower part consisting of triads. Polychords are really cool, because you are tracking two simultaneous, often unrelated harmonic sequences.
(NOTE: this is highly speculative and theoretical stuff that I MESS AROUND with. I don't really "know" what I'm doing with any of this stuff. It often goes in circles and nothing comes of it. It also mostly happens when I sit down at my synth keyboard --- with the dulcimer I seem to be returning to more traditional roots these days.)
This has been an interesting discussion, and thanks to everyone for participating. With dictionary definitions, I'm not sure I'd ever find one to be satisfying and complete, but that's just my two cents.