Lūs'trum, n.

n. [Lat., a lustration or purification, especially the purification of the whole Roman people, which was made by the censors in the Campus Martius once in five years, after completing the census, and in which an ox, a sheep, and a swine were offered; hence, a period of five years, and even more. Cf. LUSTER.] (Anc. Rome.) The space of five years.