After my switch back to Firefox from Chrome, this was one of the features I was missing. This extension works good, and does what it's supposed to do.

Just does what it says

Well done! One of the only missing pieces for making the jump to FF Quantum. Try to make it easier to find within the add-ons manager, I found it in a reddit post by googling.

I have been waiting months for FF to add an Extension/Add-On (that you can use with version FF 58+/Legacy) that gives you the definition of a word in a pop-up since their big change . Thank you so much for finally developing this. Huge thanks to krv5vignesh

Thanks!

This works like the Dictionary.com Popup in the old day. Love it. Love it. Love.

Best Dictionary addon simple to use and clean interface. Best thing is it works on android as well with double tapping on any word.

Really great add-on thank you for posting

This is exactly what I am looking for. Please make it more user friendly (like Google Dictionary chrome extension). Much appreciated. Thanks!

Love it!

This is an almost wonderful add-on.
The use of double-click is unhelpful because double- or triple- click is used to select a string of text.
How about adding a right-click menu item? or a keyboard hotkey?

Simple, lightweight, not intrusive. Would be great if allowed option to link to specific dictionaries.

There are only a very limited number of popup dicitonary plugins available for firefox quantum right now. This one does exactly what it says on the tin.

Would be nice if the source dictionaries can be referenced in the plugin description. Also, are there any plans to allow custom website look up? The best English diciotnary site I have come across so far is vocabulary.com. I think it will be worth a looking into as a potential source.