Where does “Bhagavad Gita” come from?

Bhagavad Gita (English) comes from Sanskrit भगवद्गीता, from Sanskrit गीता — song.

Ancestry of “Bhagavad Gita”, step by step

Step	Language	Word	Meaning
1	Sanskrit	भगवद्गीता	—
2	Sanskrit	गीता	song

Bhagavad Gita — Etymology, Origin & Word History | Etymology Explorer