If you try to seek out your definitions at the Google Dictionary you will be out of luck. It was closed down over the weekend.
If you go there, you get a notice that reads, "Google Dictionary is no longer available. You can use Google web search to find definitions or Google Translate for your translation needs."
Google has been closing properties recently, such as Google Labs.
There are many complaints in the Google Web Search Help forum. Kelly from Google wrote why they closed the dictionary:
As many of you know, we've recently introduced a dictionary tool into Google Web Search to help you quickly look up the definition of a word,. Because the dictionary tool offers the same functionality as Google Dictionary, we've decided to discontinue dictionary.google.com.
For your definition needs, you can type your query right into the search box and use the dictionary tool located in the left-hand panel on the results page, or you can type [define (your word)] right into the search box.
I want to thank those of who who've been loyal users of dictionary.google.com and welcome you to share your feedback on how the dictionary tool can be improved.
Again, many are not happy about this but I doubt Google will bring it back in its old form.
Forum discussion at Google Web Search Help.