How do I get rid of a Firefox add-on?

I added a dictionary thing to my browser. Whatever word you point to brings up a little window defining that word. (I did it to test the program before recommending if to an Immigrant friend of mine.)

Ah, but now I can’t get rid of it and it’s a major pain in the ass.

I went to the Firefox site but couldn’t find an answer.

I will appreciate any help.

What have you tried? The obvious thing is to go Tools, then Extensions, then Uninstall.

At the top menu bar:
Click Tools - Click Extensions
The extensions box is open.
Select the extension to remove and Click on Uninstal.
FirFox needs to then be shut down and restarted.

Thank you, thank you, thank you!!! It will be gone when I restart Firefox - which will be in two seconds.

Your welcome.