Enable dictionary to search words you dont know

So, I have Adobe on my laptop and on my desktop. On my laptop when I double-click a word and then right-click one of the features that pop up is a link to dictionary.com that shows the meaning of the word. On my desktop, however, this application doesn't appear to be there. I have googled it, but all the answers I found assumed the application would be there, and only showed you how to use it. I think I need to enable it somewhere, but I can't seem to find where. Some help would be greatly appreciated.