I assume that the same word is repeated many times, and each of these words has to be hyperlinked to the same Web page. Here is how I would go about this:
1. Create the Web hyperlink in a new document. Create it as usual in MS Word: give it any suitable text to display, and of course, associate it with the target Web address.
2. Right-click the hyperlink, and copy it (in so doing you send it to the Windows clipboard).
3. Open the document where each word has to be hyperlinked to that Web page.
4. Press “Ctrl+H” to open the Find /Replace dialog.
5. In the “Find What” box, enter the word that you want to hyperlink.
6. In the “Replace With” box, enter “^c” (without the quote marks).
7. Press the “Replace All” button. This will replace each found word with the hyperlink that you copied to the Windows clipboard in step 1 above.

HTH.
Cheers,
Robert