Where does “उसीसा” come from?

उसीसा (Hindi) comes from Sanskrit उच्छीर्षक, from Proto-Indo-Aryan ut-śīrṣa.

उसीसा (Hindi): pillow

Definitions

Step	Language	Word	Meaning
1	Sanskrit	उच्छीर्षक	—
2	Proto-Indo-Aryan	ut-śīrṣa	—

उसीसा — Etymology, Origin & Word History | Etymology Explorer