Using dictionary in Firefox with just one click
Search engines integrated into Firefox
Firefox has a small bar at the top right to use a search engine easily. Google is selected automatically but you can choose other by clicking the small arrow.
As you can see, it is possible to use search engines for items encyclopedia (Wikipedia), sales of items (eBay), etc. ...
But you can add others, such as Wiktionary, a free dictionary that seems fairly comprehensive. This is good practice to check the spelling of a word or its definition.
Installing Wiktionary
To embed a search bar to the dictionary, go to the site of Wiktionary. Once on the site, click the arrow in the search bar at the top right and click on "Add Wiktionary’’
Using the quick search Wiktionary
Now that the quick search to the dictionary was installed, click again on the arrow in the Quick Search bar and select "Wiktionary"
Then enter the word you want and press [Alt] + Enter, will open a tab with a page containing the definition of the word you are looking for.