[munificent]

Hell, I don't know what a fortnight is either!

[samdb]

From 'fourteen nights' - two weeks

[Arnavion]

Another reason to know what fortnight means is that it enables you to use the word "fortnightly" instead of "bi-weekly." With the latter I never know if the speaker meant "twice a week" or "every two weeks" without a follow-up question.

[francis88]

will add it soon. Thanks