At first I was torn between the Nook Simple Touch and the Kindle Paperwhite. I chose the Nook because of price and the absence of ads while reading a book. I had though that the Nook did not have a good dictionary function, but learned otherwise after it's purchase. All one needs to define a word from the dictionary is to place their finger on the word for two seconds and then chose the Look Up option on the bottom menu displayed on the left.