Using the example of 'Stormbreaker' $5.34 (US) a great book to entice boys to read (girls like it too). The main character 'Alex Rider' is a like a 'junior' James Bond. When students came across a word that they didn't understand I asked them to highlight it in a particular colour, the dictionary definition would come up as well. They then have to enter that meaning (in their own words) into their vocab log (a Google Spreadsheet). They would then use the word in a sentence. I limited this to 10 words a chapter. When the students met with me they would share which words they had difficulty with.
Some dictionary meanings would have more than one meaning so we would have to look at all the meanings and work out which one worked in the context of the story.
A very useful visual feature is found when you tap on a word in the text, the dictionary meaning appears down the bottom of the page but there is a link to Google and Wikipedia as well. Tap on Google and links will appear, in the example below we tapped on Waterloo (for Waterloo Station), there was no link for Waterloo Station so we added the word Station in the search field...now we have images, links and maps all about Waterloo Station. This is a great way of bringing a book to life where students can see where and what these things look like. Tapping on Wikipedia provides more information and images.
Apples iBooks that comes with the iPad does a similar thing. You can highlight words, tap on a word to get a dictionary meaning, and tap on Search Web to go to Google. The difference between this app and Kindle is that iBooks 'Search the Web' feature takes you out of the iBook app where Kindle keeps the Google search within the app and you tap the blue Done button when you want to return back to the story.
So do try this with your students, especially using the integrated 'Google' and 'Wikipedia' to find images, maps and more information about the word. You will see their vocab knowledge grow and they will become more independent about finding meanings for themselves.