English - Greek Spelling dictionary
English-Greek spell-checking dictionary for Firefox, Mozilla thunderbird and Seamonkey mail for easier spell checking in bilingual text.If you need better spelling results try the respective stand-alone...
2,739 users
Greek - English (US) Spelling dictionary
Combined Greek - English (US) spell checking dictionary for Firefox - Thunderbird - Seamonkey
266 users
English (US) Dictionary
English (US) dictionary based on the official Mozilla dictionary.
165,853 users
Grammar and Spell Checker - LanguageTool
With this extension you can check text with the free style and grammar checker LanguageTool. It finds many errors that a simple spell checker cannot detect, like mixing up there/their, a/an, or repeating a word.
374,024 users
English United States Dictionary
English United States (en-US) Dictionary as shipped with Firefox 115 ESR.
289,248 users
British English Dictionary (Marco Pinto)
A fork of Mark Tyndall's add-on, based on David Bartlett's British Dictionary R1.19 for Firefox, Thunderbird and SeaMonkey.
189,748 users
British-English Dictionary (GB)
A strict British-English spell checker dictionary for Firefox, Thunderbird and SeaMonkey. This dictionary only includes words conforming to the preferred standard of British-English spelling.
24,809 users
Canadian English Dictionary
For some reason, Mozilla doesn't have a Canadian localization team, but I know that even the British dictionary doesn't quite cut it for the truly patriotic.
25,947 users
British English Dictionary
British English Dictionary R1.19 for Firefox, Thunderbird and SeaMonkey by David Bartlett. To enable, right-click in a multi-line text box, select "Languages", then "English / United Kingdom".
7,034 users
Tenhou English UI
Change the UI text on the Tenhou HTML5 Web Client from Japanese to English
644 users
United States English Spellchecker
This dictionary is no longer maintained. Use this dictionary instead.
9,253 users
BiliBili To English
BiliBili is a video platform that only has a Chinese version. To translate its content into English, you can use this extension.
455 users
English Popup Dictionary
An English Dictionary for Firefox Quantum which gives meaning of a word which is double-click selected on a webpage.
1,370 users
Australian English Dictionary
For mad cun#s who don't speak simplified English. Packed with place names, politician names, celebrity and politician nicknames, slang and swear words. It's not perfect just yet, but it's better than what we had before and I'm constantly updating!
1,991 users
Oxford English Dictionary
Looking up Oxford English Dictionary quickly while browsing an english website
689 users
Cambridge English Dictionary
A simple add-on to look up English definitions and pronunciations in Cambridge English Dictionary online.
530 users
