A couple of years ago, I started noticing poker strategy articles that mentioned "elasticity" or "elastic/inelastic ranges." I couldn't figure out from context what they were talking about. I made a mental note to investigate this. Now that I've finally gotten around to doing so, I thought I'd share what I've learned.
Supply and Demand
We have to start with economics, because that's the source of this terminology.
The basic law of supply and demand says that, all else being equal, if you raise the price of a product, you'll sell less of it, and if you lower the price, you'll sell more.