What are the meanings of radicals?

As I've said in the introduction, Japanese is much more like English (or German, Russian, or Turkish) than you realize. Here's the secret: radicals are like letters and kanji are like words. Letters don't have any meaning by themselves. You'd never ask "Why does 'fireman' start with an 'f'? What does 'f' mean?!?", so by the same reasoning, you shouldn't drive yourself crazy asking "Why does wind (風) have an insect (虫) inside it?".[

Some radicals come from kanji, which are included in larger kanji. And sometimes, if all else fails, you can try to guess the meaning of the kanji based on the left-side radical (if it is based on a commonplace kanji). For example, the kanji for heart is 心, and most bigger kanji which include the heart radical have to do with emotions. But usually, let's face it, the radicals are meaningless.

But that's good news: since radicals are meaningless, I can just go ahead and make up arbitrary names for them. Like the cutest fucking baby birds you've ever seen in your life.

Fun fact: most Japanese aren't even aware that kanji even HAVE more than one radical. If they looked at the kanji for "rotten" (腐), they'd just see the upper-left part (which I call 'the cave'), and do the other bits a line at a time, from rote memory. That's the equivalent of only learning the first letter of a word in English and then having to memorize all the other letters by shape. This is why it takes Japanese 12 years to learn kanji.

In fact, to return to our rotten example, the other bits of the kanji are are 'stick to' and 'meat'.

Thus, instead of having to learn all 14 strokes by heart, all you have to learn is 3 radicals, and then you've learned rotten!