Mistake vs. inaccuracy: What is the difference?

I didn't write the programming or the language, but here's my best guess: An inaccuracy is more subtle and less serious than a mistake. It's still playable, and you can probably recover from it, but there was a better line. A mistake is like when you could have taken a piece and didn't, or when you could have forked the king and queen and instead forked the queen and a rook. A blunder is where you put a piece en prise with no sacrifice or combination in mind, or where you overlooked a deadly fork against yourself such as the above mentioned king / queen debacle. And, finally, a missed win is where you stare incomprehendingly at the analysis and then go bang your head against the wall for being so stupid--especially if you went on to lose the game.

I'm pretty sure that this just  depends on the difference between the evaluation result of the supposedly best move and the actual move. There are probably fixed thresholds.