Fortnight/ˈfɔːrtnaɪt/ Definition 1 of 1Pro Tip 1/3British Term Mainly used in British English and not as common in American English, where 'two weeks' is preferred. I'll see you in a fortnight. Pro Tip 2/3Future Plans Often used to talk about events that are happening soon, can be upcoming or in the near past. The festival is a fortnight away. Pro Tip 3/3Time Span Specific for indicating that something lasts for 14 continuous days. She visited her family for a fortnight.