Where does “morbillus” come from?

morbillus (Medieval Latin) comes from Latin morbus, from Proto-Indo-European mor-, from Proto-Indo-European mer- — to die; to disappear; sea, lake, wetland.

Ancestry of “morbillus”, step by step

Step	Language	Word	Meaning
1	Latin	morbus	a disease, illness, malady, sickness, disorder,...
2	Proto-Indo-European	mor-	to blacken, to dirty; dirt spot; to rub, pound,...
3	Proto-Indo-European	mer-	to die; to disappear; sea, lake, wetland

Every word from Proto-Indo-European mer- →

morbillus — Etymology, Origin & Word History | Etymology Explorer