fortnight

Fortnight is a period of fourteen days, equivalent to two weeks. In most varieties of English, especially in the United Kingdom, it is a standard unit of time used in everyday speech and writing: for example, one might say, “I’ll be away for a fortnight.” In American English, the phrase is uncommon, and people typically say “two weeks” instead. Fortnight is widely found in calendars, contracts, travel plans, and payroll schedules.

The term derives from Old English feortan niht, literally “fourteen nights.” It entered Middle English and has survived into modern English with the spelling fortnight, preserving the sense of a fourteen-night span rather than a precise count of days. The term’s usage dates to medieval and early modern periods and remains part of standard British English today.

Fortnightly is an adjective and adverb meaning occurring every two weeks, or published every two weeks. The alternative term biweekly can be ambiguous in American usage because it may mean twice per week or every two weeks, depending on regional usage.

Applications include rental periods, payment schedules, and travel or project planning. While practical and precise, the term is less common outside regions that favor British English, and in formal writing people may prefer “two weeks.”