Where does “tan rã” come from?

tan rã (Vietnamese) comes from Vietnamese rà, from Latin rēx, from Proto-Italic rēks, from Proto-Indo-European h₃rḗǵs, from Proto-Indo-European h₃reǵ- — to straighten, to right oneself; right; just.

tan rã (Vietnamese): to break up; to disintegrate; to fall apart

Definitions

to break up; to disintegrate; to fall apart

Ancestry of “tan rã”, step by step

tan rã traces back through two separate lines of ancestry.

via Vietnamese rà

Step	Language	Word	Meaning
1	Vietnamese	rà	to check
2	Latin	rēx	king, ruler
3	Proto-Italic	rēks	king
4	Proto-Indo-European	h₃rḗǵs	king, ruler
5	Proto-Indo-European	h₃reǵ-	to straighten, to right oneself; right; just

via Vietnamese tàn

Step	Language	Word	Meaning
1	Vietnamese	tàn	ashes; remains; residue; to fade; to wither; to...
2	Chinese	秦	—

Every word from Proto-Indo-European h₃reǵ- →Every word from Proto-Indo-European h₃rḗǵs →Every word from Proto-Italic rēks →