Where does “जेठानी” come from?

जेठानी (Hindi) comes from Prakrit 𑀚𑀺𑀝𑁆𑀞𑀸𑀡𑀻, from Sanskrit ज्येष्ठ, from Proto-Indo-Iranian *ȷ́yáHištʰas.

जेठानी (Hindi): husband's elder brother's wife

Definitions

Step	Language	Word	Meaning
1	Prakrit	𑀚𑀺𑀝𑁆𑀞𑀸𑀡𑀻	—
2	Sanskrit	ज्येष्ठ	most excellent, pre-eminent, first, chief, best,...
3	Proto-Indo-Iranian	*ȷ́yáHištʰas	—

जेठानी — Etymology, Origin & Word History | Etymology Explorer