Yes, I wasn't being totally serious. Pro-metric people sometimes jokingly refer to the 'imperial' 3F system by analogy with the SI system and others. I think '

Yes, I wasn't being totally serious. Pro-metric people sometimes jokingly refer to the 'imperial' 3F system by analogy with the SI system and others. I think 'Fortnight' is rapidly falling out of use in British English. I would be much more likely to say 'a couple of weeks'