Where does “ग्रेट ब्रिटेन” come from?

ग्रेट ब्रिटेन (Hindi) comes from English Great Britain, from Middle English Great Brittaigne.

Ancestry of “ग्रेट ब्रिटेन”, step by step

Step	Language	Word	Meaning
1	English	Great Britain	—
2	Middle English	Great Brittaigne	—