In pictures: 10 free Google Chrome extensions to i...
Google Dictionary: Look Up Words With a Double Click
Google Chrome does come with its own built-in dictionary, but it takes a number of clicks to reach it. The Google Dictionary extension lets you find the definition you need with just a double click. For this to work, though, you need to go to the Options and enable "Display pop-up when I double-click a word."
In pictures: 10 free Google Chrome extensions to increase your productivity