A fortnight is a unit of time equal to 14 days (2 weeks). The word derives from the Old English term fēowertyne niht, meaning "fourteen nights".

What is the meaning of Forth nightly?

: a period of 14 days : two weeks They stayed with us for a fortnight.

What is the origin of fortnight?

Fortnight comes from the Middle English fourtenight, which is contracted from the Old English fēowertēne niht. We suspect you don't need to be a time-traveling Anglo-Saxon to see how fēowertēne niht means “fourteen nights.”