English United States Dictionary per Jorg K

This add-on provides the Mozilla-maintained Hunspell US English dictionary that is shipped with Firefox 115 ESR as an add-on for localized versions of Firefox.

It is based on the SCOWL (and friends) "normal" dictionary size with accented words (like "café"), common variants, "hacker" terms and Roman numerals.

It also has additional 2500 Mozilla-added proper names and 37 Mozilla-specific terms.

This dictionary is different from the "other" US English dictionary provided on the AMO site which is no longer maintained. The "other" dictionary uses the "large" SCOWL size ("size 70") and also contains accented words and common variants. This and the other dictionary are both an excellent choice depending on your needs.

Summarising:

• This add-on which is the Mozilla-distributed dictionary: "Normal" size, accented words, common variants, additional 2500 proper names, 37 Mozilla-specific terms.
• The other add-on: "Large" size, accented words, common variants.

Note: This add-on has changed. Before it distributed the "large" SCOWL dictionary, but since the other add-on has now switched to the same, it now distributes the Mozilla dictionary instead.