nounpl. -·trums or -·tra
- in ancient Rome, a purification of all the people by means of ceremonies held every five years, after the census
- a five-year period
Origin of lustrumL, origin, originally , probably illumination from Indo-European an unverified form leukstrom, illumination from base an unverified form leuk-, to light, shine from source light
nounpl. lus·trums, or lus·tra
- A ceremonial purification of the entire ancient Roman population after the census every five years.
- A period of five years.
Origin of lustrumLatin lūstrum ; see luster .
From Latin lustrum (“period of five years").