Kindle3 comes with a pre-installed dictionary, the new oxford American dictionary, and you can look up the words you're not familiar with while you're reading a book. But the OAD aimed primarily at a native speaker of English, so it's not the best choice for a learner of English to tackle with.
I've kept using it for the last several books, but about half the times I looked up some words, I couldn't make out right away the meaning of the definition, which is displayed either at the bottom or the top of the screen. It's quite easy to look up words on kindle3, just to move a cursor to the word you want to look up, but the space for the definition to appear is very limited; only two lines of explanations are available to read. To read farther definitions, you've got to click the arrow sign and go to the full screen mode. If you repeat this, you have to stop your reading often and you're unlikely to enjoy the book at its best.
To diminish the nuisance and fulfill the joy of reading, I've decided to change the dictionary from OAD to Collins Cobuild Advanced Learner's dictionary of British English. I prefer to use an American English dictionary, but there are not many selections of kindle version dictionaries at the moment and CCAL? seems to be the only choice for now to buy.
Having an easier and more detailed dictionary installed in my kindle3 now, I'm supposed to be enjoying the book easily and thoroughly, but it won't be that easy to acquire the joyous and fulfilled moment. That's because the choice of my books. I sometimes read very nerd and dirty stories, so quite often I bump into rarely used words in everyday life. For those not popular words, any dictionaries I can buy in the style of book won't satisfy my need. I need to look them up on an online dictionary such as urban dictionary. I wonder if I should bookmark the site of urban dictionary and use it when I'm dying to know the meaning of irresistible unfamiliar words...
どの辞書にしよーかなー、と迷う楽しみもなく、Collins Cobuild Advanced Learner's dictionary of British Dictionary を買いました。あとシソーラスも欲しいんだけど、何がいいかな？