For me, it also doesn't work. macOS Ventura 13.4.1

not working anymore

I have been looking for this for so long.

Firefox 105.0.1 and macOS Monterey 12.6: plugin working like a charm. I've been stuck with Firefox to work (I rather use Safari) and I was *badly* missing 'Lookup'. Thank you, Emmanuel!

Does nothing. Firefox 91.8.0 ESR on Mac OS X 10.14.6.

Works in Big Sur (OS 11.3.1), but you still have to select "look up in dictionary" at the bottom of a pop-down menu, so I wouldn't call it automatic. But you do get the Mt. Rushmore of Mac OS's dictionary, thesaurus, "Apple" and Wiki! Thanks.

Works on Catalina (10.15.7) with Firefox Proton versions.

Though not so simple to get going with.

You need to enter "dict://" into the address bar and choose the OSX system dictionary. It will now work for you from now on.

Clearly a bug that needs fixing.

It works on my Big Sur, but sadly not in the way I expected. After click "look up", it doesn't show the result directly as in Safari and Chrome, you have to switch to the Dictionary application manually to see the result.

I works fantastically in my Big Sur macbook. What you have to do is to allow firefox to always run the MacOS Dictionary by typing "dict://test". in the address field of your FF browser and click "always..." and now it will always work.

Works on big sur (11.2.3) with Firefox 87.0. Simple yet effective, thanks for sharing this!

This extension adds a "Lookup in dictionary" option when you right click a selected word on a page. What this does is open the as "dict://". You can try the same thing from the browser bar. E.g. type "dict://test". I noticed that I first had to use the "dict://" URI from the browser bar manually and associate it with the OSX Dictionary application before the plugin would actually do something for me.

This app doesn't work. Why is it so hard to get Firefox to do a simple function which is define a word?

works as expected on Big Sur 11.2.3 and Firefox 87

used to work, until Big Sur.
Now, sadly, nothing happens. Version 1.3.3

debuggee 'resource://devtools/shared/base-loader.js:289' would run builtin-modules.js:196:11
window.gBrowser is undefined ContentDispatchChooser.jsm:71
handleURI Choo
AsyncFunctionThrow self-hosted:678

Doesn't work - simply doesn't do anything at all.

Not working out-of-the-box on Big Sure :-/ Looks neat though!

Giving it 3 stars because it used to work, but for me has stopped (Mac High Sierra).

Doesn't work for me (macOS Mojave).

This doesn't work in macOS Catalina. It worked in Mojave.

This extension did not work for me with macOS 10.15.6. I downloaded and installed it, refreshed a page, selected a word and right clicked and … nothing happened.

To the developer, thanks for writing this extension, I look forward to using it once it's working reliably.

I can confirm that this does not seem to be working on either macOS 10.15.5 or macOS 10.12.6. Is this still being supported by the developer?

Like Firefox user 15573474, I'll update my rating to five stars once the add-on is working again.

UPDATE: Hi Emmanuel, thanks for your reply. I've just updated my macOS to 10.15.6; I don't know if it's something in my settings, but the dictionary is still not opening for me when I select a word, right click, and choose "Look up "[selected word]" in Dictionary." Nothing seems to happen at all, in fact. Please keep me updated if there are any further developments. I'll remove the two-star rating, since I know you're working on it.