Definition of flash fiction

Don't do it! they say, but I can't stop asking. I'm certain that others have defined the form much better but this is where I got to so far:

I've been pondering this thing I call conceptual resonance. Simple example: Concept 1: frigidity. Concept 2: snow. Or: Concept 1: happiness. Concept 2: Sunshine. These concepts resonate on a very basic, almost vulgar level. Other concepts resonate on more complex, subtle, strange or crazy levels. Someone probably has an official name for it.

So, poetry is all about conceptual resonance. Story is irrelevant. In a poem you can just scrawl out your concepts any old way and hope they resonate in a pleasing way.

Flash is poetry + story. Conceptual resonance is still important, but you need a story too. You can't just waffle on about happiness and warmth. You need happy Carl to be trying to find a way to pay his heating bills. You need some story elements.

Short story up to novel also = conceptual resonance + story ... but ... the conceptual resonance is much diminished and story is much more important. Plot comes to dominate.

Why so? It's s a basic question of length. In very simple terms, because Flash is short (that's a given), all the concepts you deploy are going to bump up against each other. It can't be helped. Resonance becomes a vital factor to the reading experience. It's possible to write a Flash piece almost entirely as story but very boring, like this one:

Carl is cold. He has no money. So he decides to rob a bank. He succeeds! Now he has lots of money. No more problems with those heating bills.

As soon as you try filling in the details here - who Carl is, how it actually unfolds, you need to deploy concepts. They're the coloring in. The really good ones almost always, in my experience, run new and interesting concepts together that create resonance not seen before.

So, that's the definition. Flash is poetry + story balanced out in relatively equal importance. And where does that leave microfiction? Microfiction is just very short flash. A sub class.

I am sure that this is either really obvious, wrong, well-discussed or misuided. But it's what's rattling around the old head these days, and I have to get it down, pat, if only for my own benefit.