http://en.wikipedia.org/wiki/Synergy - it defines pretty good what I mean.
Yeah, no, not really. By that definiton any headphone and any amplifier are synergetic because the headphone cannot amplify the signal on its own. Not only that every headphone and every amplifier create a unique sound of their own so they all have synergy, do they not. Therefore I think it would be hard by that definiton to make the claim that one chain of components has better synergy than another unless you are stating some kind of goal that you are working towards in terms of a final balance or sound.
Basically all you have to say is that you think the components pair well rather than making such cryptic statements. It's just easier and less misleading if you just speak in a straight forward manner.