Where does “articulus” come from?

articulus (Latin) comes from Latin artus, from Proto-Indo-European h₂értus, from Proto-Indo-European h₂er- — to fit, to fix, to put together.

articulus (Latin): A point connecting various parts of the body;...

Definitions

Step	Language	Word	Meaning
1	Latin	artus	narrow, close, fitted, confined, dense; severe,...
2	Proto-Indo-European	h₂értus	that which is fit together; juncture, ordering
3	Proto-Indo-European	h₂er-	to fit, to fix, to put together

articulus — Etymology, Origin & Word History | Etymology Explorer