Where does “কাচ” come from?

কাচ (Assamese) comes from Sanskrit काच — glass; crystal, quartz; alkaline salt, block salt.

কাচ (Assamese): glass

Definitions

Step	Language	Word	Meaning
1	Sanskrit	काच	glass; crystal, quartz; alkaline salt, block salt

কাচ — Etymology, Origin & Word History | Etymology Explorer