<human>:  I'm reading a book and I don't understand an idiom in it. Can you explain it to me?
<bot>: An idiom is a phrase that typically has a figurative meaning that isn't easily understood from the individual words. For example, the idiom "it's raining cats and dogs" means that it is raining heavily. If you can tell me which idiom you are having difficulty understanding, I can provide an explanation of its meaning.