Where does “हेतु” come from?

हेतु (Hindi) comes from Sanskrit हेतु, from Sanskrit तु, from Sanskrit त्वम्, from Proto-Iranian tuHám, from Proto-Indo-Iranian túH, from Proto-Indo-European túh₂ — you, thou.

हेतु (Hindi): cause, reason; motive

Definitions

cause, reason; motive

Ancestry of “हेतु”, step by step

Step	Language	Word	Meaning
1	Sanskrit	हेतु	"impulse", motive, cause, cause of, reason for;...
2	Sanskrit	तु	pray, I beg, do; but; and
3	Sanskrit	त्वम्	you, thou
4	Proto-Iranian	tuHám	—
5	Proto-Indo-Iranian	túH	you, thou
6	Proto-Indo-European	túh₂	you, thou

Every word from Proto-Indo-European túh₂ →Every word from Proto-Indo-Iranian túH →Every word from Proto-Iranian tuHám →