The spell checker tool needs to be update, it comes up with items that are real, well-known words in English (e.g. DVDs, responders).
system
2
The spellchecker’s database is dynamic and learns new words based on how users answer the question of whether the word is misspelled or not. When you encounter a word that is not a spelling mistake, and you hit “No” to say that it is not a misspelling, the system records that vote, and if enough users vote “No,” the spellchecker “learns” that word and it won’t ask for it to be corrected in the future.
So the best thing to do is to accurately report if words are misspelled or not, and the database will grow to include these terms. There is no “master list” that we add to manually, as far as I know.
@Anna
may have more to add, or correct me if I’ve misrepresented how it works. I know there was a forum post about this when the new spellchecker was introduced a while back, but it wasn’t easily found searching the forums.