Even in this multimedia world words retain their importance and occasionally we and our students need to assure ourselves of what they mean and how they can be used. Google itself can provide interesting information on word use and collocations (try searching for wristwatch, wrist watch and wrist-watch) and of course the Internet provides a range of online dictionaries for all tastes. Here are my favourites.
http://dictionary.reference.com/ (Dictionary.com) is a simple but effective place to start!
Major publising companies have their own online dictionaries such as Macmillan http://www.macmillandictionary.com/ where along with simple definitions you get so much more.
My favourite, however, is http://ninjawords.com/ The fastest and simplest dictionary ever! What is also useful is that it keeps a record on the right of the words you have searched for. This can be used very effectively if working with a class or IWB.
For something more stunning and multimedia-friendly try exploring http://www.visualthesaurus.com/. This provides a wonderful graphical illustration of any search.
Finally, another multimedia word presentation. http://www.wordcount.org/main.php will show you visually where your choosen word is placed within the 86,800 most common words in English. Great fun and actually very useful.