Yesterday, a poster on campus informed me that we are in the middle of Fairtrade Fortnight. As a non-native English speaker I used to see fortnight as a word used only by characters in Shakespeare plays and old people, but when I moved to the UK, I realized that it is actually commonly used. I am sure you would be seen as quite the eccentric were you to use it in America though.
Fortnight comes from the Old English feowertyne niht and simply means ‘fourteen nights’. Interestingly, though, not that many languages have one single word for that particular unit of time. In Norwegian, for instance. we say ‘fourteen days’ (fjorten dager). Sometimes, a contraction of that (fjortendager, or fourteendays) is used in casual speech, but you cannot use it in writing. It is also more common to use it when talking about something that happened in the past or will happen in the future than something that is going on right now (like Fairtrade Fortnight).
Like Norwegian, most other languages count the days rather than the nights when talking about this unit of time. The Italian una quindicina di giorni means ‘fifteen days’, as does the French une quinzaine de jours. The reason why some languages use fifteen rather than fourteen days (or nights) is that one half of a Lunar month is between fourteen and fifteen days.
A language that actually does have a single word for the two-week period, and that counts nights rather than days, is Welsh, with pythefnos, which means ‘fifteen nights’. Apparently, the custom of counting nights comes from the Germanic tradition.
I remember the first time a dentist’s secretary told me they could book me in ‘a fortnight from now’, and how old-fashioned and incredibly English it sounded. I think I might need a few more years here before I am ready to use it myself.