Dictionary.com Toolbar 

The Dictionary.com toolbar is an add-on for your browsers. There are versions for both Internet Explorer and Mozilla Firefox. The bar allows you to use a variety of Ask.com services, among which is dictionary.reference.com. Depending on the browser you use, the bar will be installed and located either below the address bar or somewhere near it. From the toolbar, you can prompt any of the ask.com services. You can ask any type of question that you want to Ask. You usually get good results. But the best use I can think of for this application is the dictionary part of it. I use dictionaries a lot, and having them on a single location proves incredibly helpful. The bar is made up of a text field, where you type your text, and a drop-down menu, which allows you to choose among all the ask.com services. Also there are links to the Dictionary.com dictionary and thesaurus. The lexical service is great and very accurate. I like Cambridge's online dictionary a little better, but the toolbar works from your browser and is more easily accessible.