A period of five years.
- ‘37 years ago my first secretary was a lady who has remained my friend for nearly 8 lustrums (4 decades) and today is a leading lady lawyer in Los Angeles who has never lost a case in court.’
- ‘The book is dedicated to Nygren's wife Irmgard "in thankfulness for seven lustrums of theological cooperation."’
Late 16th century: from Latin, originally denoting a purificatory sacrifice after a quinquennial census.