lustrum

1. (historical) A lustration: a ceremonial purification of the people of Rome performed every five years after the census.Examples: "[A]ll theſe Magiſtrates were elected by, and from, the whole promiſcuous Body of the People in their public Aſſemblies; that after the Inſtitution of Cenſors, it was look'd upon as a Matter of Form only, that they should enroll the new Senators at the next general Luſtrum, or Survey of the Commonwealth; […]"; "The interval of time supposed to have been denoted by the Roman Lustrum has been made the subject of controversy. No one however as far as we know has ever assumed it at less than four years or as more than five; so that the status quæstionis may so far be considered as fixed and agreed upon: and all that we have to do at present is to begin with inquiring whether the Roman Lustrum was more properly a period of five years or one of four."historical

2. (by extension, literary) Synonym of quinquennium: Any 5-year period.Examples: "We puſh Time from us, and we wiſh Him back; / Laviſh of Luſtrums, and yet fond of Life; / Life we think long, and ſhort; Death ſeek, and ſhun; […]"; "Thus passed away two lustra of her life, and, as yet, my daughter remained nameless upon the earth. "My child," and "my love," were the designations usually prompted by a father's affection, and the rigid seclusion of her days precluded all other intercourse. Morella's name died with her at her death. Of the mother I had never spoken to the daughter;—it was impossible to speak."; "I am hardly, if I do not deceive myself, twenty years old, and already, dearest Rosamunda, there weigh upon my existence twenty lustrums, and of these twenty lustrums I have drunk the bitterness of intranquility even to the dregs, without having done more than touched with my lips the joy of the first days of my childhood beside you."Synonyms: quinquenniumbroadlyliterary