In-Depth Explanation of the Audio Term "Synergy"

Hello: I've read and heard the term "synergy" bandied about frequently since getting into audio. Just the other day, an audiophile friend of mine said in an email. "Regardless of gear brand, I feel synergy is the most important thing to try and achieve really." This term "synergy" gets thrown around often and very easily. Most often I've heard this term used in the phrase, "amplifier-speaker synergy is the most important element of an audio system." I've always felt that if you put together a system and it sounds good to you or sounds "right", you have a system with amp/speaker synergy. I also felt that if your amplifier works with your speakers as it is designed without straining, clipping, running too hot, remaining stable etc., and produces good sonics with your speakers, then you have achieved synergy between your amp and speakers. I do an awful lot of research on the internet for all things audio (much to my wife's chagrin) and I've read several articles that discuss synergy. None of the articles I've read give a definitive and in-depth explanation of what "synergy" between a power amplifier or integrated amplifier and the speakers connected to it actually entails. So, I'm asking other audiophiles: What does "synergy" between an amplifier and speakers actually entail? Does anyone really know, or is this just one of those generalities that audiophiles put out there? What elements are really involved when synergy exists between the amplifier and speakers? I've always been curious about this subject