plural lustrums or lustra
ˈlə-strə 
1
: a period of five years
2
a
: a purification of the whole Roman people made in ancient times after the census every five years
b
: the Roman census
Cite this Entry
“Lustrum.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/lustrum. Accessed 3 Nov. 2025.
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