The turn of the century is the transition from one century to another, or the time period before or after that change in centuries.

The standalone "turn of the century" phrase is generally understood to mean the change (whether upcoming or past) closest to the current generation. During the 20th century, the phrase was used to refer to the transition from the 19th century to the 20th century. With the dawn of the 21st century, the century is often indicated to avoid confusion.^{[1][citation needed]}

The Chicago Manual of Style has indicated some ambiguity on the exact meaning of the phrase "turn of the n-th century". For instance, if a statement describes an event as taking place "at the turn of the 18th century", it could refer to a period around the year 1701 or around 1800, that is, the beginning or end of that century. As a result, they recommend using either only "turn of the century", in a context that makes clear which transition is meant,^[2] or alternatively a different expression that is unambiguous.^[3]

• Fin de siècle
• Progressive Era
• Edwardian Era
• Information Age
• War on Terror