What is Interaction Design?

What really is interaction design? Ranjeet Makkuni once asked me this same question. I told him that its designing the interactions between a machine and a human being. “So what would you call this?” He asks holding a flute in front of me. “Is this interaction design or not?” I look at the flute… see each and every bore and the taper at the end where the lips touch the instrument. A simple piece of bamboo. And then realization dawns. “Yes”. I admit. Suddenly this man has managed to humble my IIT ego and put forth a very simple understanding. He blew into it and few melodious notes rand out. “Look at this… is it not interaction design at its most simple and basic level? I interact with this ‘machine’ and see what comes out of it!” He smiled.
Suddenly after 6 and a half years of being a design student and trying to find the right answer for the question- this man had managed to teach me the same in a matter of 52 seconds.