

I think in combination with “The Sunday thread” it’s unambiguous?
Perhaps, though I guess it could also be that there is “The Sunday thread” and “The Wednesday thread”.
As for whether fortnightly is common or not, I think it is, but the other commenter suggests that only the Brits use the term. Fairly certain I’ve heard that from an Aussie friend though, could be that US Americans don’t use the term.
Perhaps semimonthly is the most unambiguous term? That’s what Mariam-Webster seems to suggest.
True, didn’t think it that way. I don’t know what would be best, English is such a wierd language.