Is there an easy-to-articulate difference between a polaron and an electron exhibiting electron-phonon coupling? Until yesterday, I had been under the impression that the difference between the two phenomena was related to the strength of the coupling. However, I looked up "polaron" on Wikipedia, and the lede paragraph left me confused. The definition listed by Ashcroft & Mermin is similarly vague (see p. 626). If there is no meaningful difference between the two concepts, it seems to me that electronic quasiparticles ought to more properly be called polarons in in basically every solid ever, since it is hard to imagine a crystal where the electronic forces between electrons and the ions have no effect.