SG Heritage Dictionary

Lustrum [Adjective] Webster's Dictionary 1828

Lustrum [Noun] Webster's Dictionary 1828

In ancient Rome, the space of five years.

Lustrum [Noun] Webster's Dictionary 1913

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.

Lustrums [Plural] Webster's Dictionary 1913

of Lustrum