Merriam-Webster Online

Ever want to look up words on the fly when surfing around or just for the hell of it. Well, let me tell ya somethin'. This toolbar is the thing to have. I haven't been able to load it yet, one major minus, but just think...a google toolbar and a dictionary toolbar right next to each other. Every geek's dream. Find anything and define it all at the same time.
If need be, you can install the lookup button which lets you highlight a word and get the definition at a click of the button on your Links toolbar (in IE) or in the Personal toolbar in Netscape. Haven't figured out the connection between Netscape and Mozilla yet but I know there is one. C-ya!