I don't recall if there's been a definitive answer as to what words are included, has anyone else read anything about it? I remember reading at the beginning it was meant to be a list of 2000 common words, but a few of the previous words don't seem to have been very commonly used words.
The other games like Quordle etc seem to use all 5 letter words, even if they are very obscure.
Regarding plurals, someone in the earlier threads said that there are no plurals (ie with s's) in, which does seems to have been the case so far. Maybe US english uses fungi (funghi!) as a singular as well?