From within Firefox, click on the appropriate link below and then click on the
"Install Now" button in the dialogue box. You may have to
select Firefox as the application to use to open the extension when prompted.
(Note: Even though this extension is unsigned, Merriam-Webster has
determined that it is safe to install and use.)
Click the "Install" button. The Firefox "Extensions" box will open, showing a "Dictionary Search" with a
green icon. Close this box, and all other Firefox browser windows, then restart Firefox to complete
installation.
Select "Tools" -> "Extensions" from the menu bar. This extension will appear as "DictionarySearch" in the listing—select it and click on the "Options" button:
A new dialogue box will open. Under Dictionary 1, copy and paste
the following text into the "URL" box (be certain to include the '$' at the end of
the URL):
Note: This download is not compatible with Internet Explorer or Netscape. To install a similar feature into one of those browsers, see the Merriam-Webster Lookup Button.