The service is free. To add it to your computer, download a small file from the Web. You must be online for it to work.
The site combines the functions of a thesaurus, dictionary and encyclopedia and is a handy reference tool.
To use the site, place your cursor over the word you want to look up, tap "alt" on the keyboard, and click the left mouse button.
Tom clicked on the word "AIDS" on the WRAL OnLine Web site and up came a definition. The pop-up box also gave him acronyms. Translations are available; so far, the service translates only into Spanish, though.
If you click on a public company name, you get stock prices and Web addresses.
GuruNet could not come up with a meaning for "SprintCom," but it did allow Tom to do a quick Web search for the term.
GuruNet.com also works in e-mail programs and newsgroups.
The service was developed in Israel and more features are planned, including a way to look up area codes.