Where does “ৰোক” come from?

ৰোক (Assamese) comes from Assamese কোৰোক, from Assamese কোৰ, from Sanskrit *कोरति.

Ancestry of “ৰোক”, step by step

Step	Language	Word	Meaning
1	Assamese	কোৰোক	—
2	Assamese	কোৰ	—
3	Sanskrit	*कोरति	—

ৰোক — Etymology, Origin & Word History | Etymology Explorer