Where does “lustrum” come from?

lustrum (Dutch) comes from Latin lūstrum, from Old Latin loustrom, from Proto-Indo-European lewkstrom, from Proto-Indo-European lewk- — bright; to shine; to see.

Ancestry of “lustrum”, step by step

Step	Language	Word	Meaning
1	Latin	lūstrum	bog, morass, place where boars and swine wallow
2	Old Latin	loustrom	—
3	Proto-Indo-European	lewkstrom	—
4	Proto-Indo-European	lewk-	bright; to shine; to see

Words derived from “lustrum”

lustrum

Every word from Proto-Indo-European lewk- →Every word from Proto-Indo-European lewkstrom →Every word from Old Latin loustrom →