Lustrums, also known as five-year periods, can be referred to as quinquenniums, quinquennials, or simply five-year cycles. These synonyms may be used in various contexts, including in the business world to refer to strategic planning or budgeting cycles, or in academia to denote tenure reviews. The term lustrum originated from ancient Rome, where a lustrum was a purification ceremony performed every five years. While not commonly used in modern English, it is still useful to know synonyms for lustrums in order to effectively communicate within various industries or academic circles.