LUSTRUM

lustrum

(noun) a ceremonial purification of the Roman population every five years following the census

lustrum

(noun) a period of five years

Source: WordNet® 3.1

Etymology

Noun

lustrum (plural lustra or lustrums)

(Ancient Rome, religion, historical) A ceremonial purification of all the people, performed every five years after the taking of the census; a lustration. [from late 16th c.]

(by extension, literary) A period of five years.

Synonyms: luster, lustre, quinquennium

Notes

Source: Wiktionary

Lus"trum, n.; pl. E. Lustrums, L. Lustra. Etym: [L. Cf. 2d & 3d Luster.]

Definition: A lustration or purification, especially the purification of the whole Roman people, which was made by the censors once in five years. Hence: A period of five years.

Source: Webster’s Unabridged Dictionary 1913 Edition