Where does “arcușor” come from?

arcușor (Romanian) comes from Romanian arc, from Latin arcus, from Latin solium, from Proto-Indo-European sodyom, from Proto-Indo-European sḗd- — to sit.

Ancestry of “arcușor”, step by step

Step	Language	Word	Meaning
1	Romanian	arc	bow; arch; arc
2	Latin	arcus	arc, arch; bow; rainbow
3	Latin	solium	seat, chair; throne, chair of state, official...
4	Proto-Indo-European	sodyom	—
5	Proto-Indo-European	sḗd-	to sit

Every word from Proto-Indo-European sḗd- →Every word from Proto-Indo-European sodyom →Every word from Latin solium →