lustrum

Etymology

From Latin lūstrum.

noun

1. (historical) A lustration: a ceremonial purification of the people of Rome performed every five years after the census.
   [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; […] 28 February 1746, “A Treatise on the Roman Senate, in Two Parts. By Conyers Middleton, D.D. Principal Library-keeper of the University of Cambridge. Printed for R. Manby, and H. S. Cox, 1747. Octavo. 169 Pages.”, in The Museum: Or, The Literary and Historical Register, volume II, number XXV, London: Printed for R[obert] Dodsley[…], →OCLC, page 409
   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. 1854, Edward Greswell, “Dissertation X. On the Lustral Cycle of the Romans and on the Initia Censoria”, in Origines Kalendariæ Italicæ, Nundinal Calendars of Ancient Italy, Nundinal Calendar of Romulus, Calendar of Numa Pompilius, Calendar of the Decemvirs, Irregular Roman Calendar, and Julian Correction. Tables of the Roman Calendar, from U.C. 4 of Varro B.C. 750 to U.C. 1108 A.D. 355. … In Four Volumes, volume II, Oxford: At the University Press, →OCLC, chapter I, section II (On the Proper Measure of the Lustral Cycle), page 248
2. (by extension, literary) Synonym of quinquennium: Any 5-year period.
   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; […] 1742–1745, [Edward Young], “Night the Second. On Time, Death, Friendship. Humbly Inscrib’d to the Right Honourable the Earl of Wilmington.”, in The Complaint: Or, Night-thoughts on Life, Death, & Immortality, London: Printed for A[ndrew] Millar[…], and R[obert] Dodsley[…], published 1750, →OCLC, lines 172–174, page 29
   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. 1835 April, Edgar Allan Poe, “Morella”, in The Southern Literary Messenger: Devoted to Every Department of Literature, and the Fine Arts, Richmond, Va.: T. W. White, →OCLC; republished in The Works of Edgar Allan Poe: In Four Volumes, volume I, New York, N.Y.: W. J. Widdleton, publisher, 1849, →OCLC, page 473
   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. 1852, Adadus Calpe [pseudonym; Antonio Diodoro de Pascual], chapter XIV, in Henry Edgar, transl., The Two Fathers. An Unpublished Original Spanish Work. … Translated into the English Language by the Author, and Henry Edgar. Part Second: Hector Alone, New York, N.Y.: Stringer & Townsend, publishers,[…]; George P[almer] Putnam,[…], →OCLC, page 189
   Q. Now, sir, if you would be so kind as to guess upon his age. / A. Forty five years are certain. I would guess a lustrum more. 1985, John Fowles, A Maggot, London: Jonathan Cape