Where does “Brahmana” come from?

Brahmana comes from Sanskrit ब्राह्मण, ultimately derived from Proto-Indo-European bʰerǵʰ-.

Ancestry of “Brahmana”, step by step

Step	Language	Word	Meaning
1	Sanskrit	ब्राह्मण	relating to or given by a Brahmin, befitting or...
2	Sanskrit	ब्रह्मन्	pious effusion or utterance, outpouring of the...
3	Proto-Indo-European	bʰerǵʰ-	to rise; high, lofty; hill, mountain

Brahmana — Etymology, Origin & Word History | Etymology Explorer