Its strange American English created this ambiguity in usage. There's a perfectly good english language noun which means "2 weeks". The word is "Fortnight".

We use it all the time here in Australia - eg "This is a fortnightly meeting" / "Lets meet back up in a fortnight and discuss progress".

I consider teaching "fortnight" to americans a gift I insist on giving to every american colleague I work with. Its already in your dictionaries, after all. Please use it, and you're welcome!