As a deity name
Name 335 of the Gayatri Sahasranāma — Devi Bhagavata Purana, as taught by Sages
As a Hindi name
No reading on this path — this spelling has no entry in our Hindi sources, and no near neighbour is attested there either. We say so rather than invent one.
As a Sanskrit word
Meaning
The Ganges. E. jahnu, and tanayā the daughter; the river in its course disturbed the devotions of the saint JAHNU, upon which he drank up its waters; having released them at the in…
Scripturally attestedWhy this matches what you typed
M1 · same meaning "jahnutanayāyai" is the dative of "jahnutanayā" — the same word in a different grammatical case.
Dictionary citations
jahnu—tanayā f. id., L.
jahnutanayā f. (-yā) The Ganges. E. jahnu, and tanayā the daughter; the river in its course disturbed the devotions of the saint JAHNU, upon which he drank up its waters; having released them at the intercession of BHAGĪRATHA, he is thus considered as the parent of the stream: see jāhnavī; also jahnusutā, &c.
Caveats
Sources contain errors and engines have limits; every claim above carries its citation so you can verify it. This is guidance about names and their sources — not religious or astrological consultation. How we work · Our sources