I think could be the best add on with a few tweaks. It very simplistic which is a great thing . there's been some go I d suggestions and mine are things that would make more functional and not take away from the simplistic flow.
The 1 time I want to be a lefty ;) . I'm right and mostly on a tablet or phone so when I highlight I r double click the yellow popup is under my hand. It sounds minor but enough of an inconvenience that I will need to continue my search if a future update is not added for an option for choosing the popup side.
Doesn't need to be fixed as it's not broke but I don't like the delay and inconvenience. I wish Samsung would make a feature when you hover the Pen over a word the definition would pop up as they have pictures and hyperlinks. I think developer has done great job and would love to continue using but the amount I utilize now since getting larger phone I am only the option of some costly clunky app that's way overkill for just what's done here solely with a tiny addon.
If wanting to elaborate on addon as maybe a Pro version, I would say the Ability for us to choose or enter the site used to lookup, Choice from a few colors or a pallete of popup box, Addition of a speaker icon by word to hear it sounded out.
Now the last may be too much to ask for but that's basically what I or know others utilize. Not all these games,words of the day,share the word with everyone and just so much distracting and phone memory using features.
While browsing all needed is - reading,what's that word, click, what's the meaning, how's it sound, continue reading. Perfect App!

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.