You'd think that everything that needed defining would be in a dictionary or a reference book. Unfortunately for those of us not gifted with the innate ability to understand the fuzzier aspects of life (such as what is polite in what circles) [read with sarcasm the "gifted with the innate ability", please...] ... it's obvious that NOT everything is clearly defined.
For instance, something I've wrangled with for years... what in tarnation is a "favorite color"?? I still don't have a definition, but I do have a good feeling for it that could turn into a definition if pressed, though it's unlikely that that would be a fully accurate definition.... you'd get a different answer if you asked 20 minutes later, probably.
Many of these rants/thoughts are the direct result of me attempting to find a definition for myself that agrees with the rest of the world as best as possible, defining those areas that the rest of the world doesn't seem to have bothered to.