As a deity name
Name 389 of the Saraswati Sahasranāma — Skanda Purana, as taught by Lord Brahma / 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
having a great body
Scripturally attestedWhy this matches what you typed
M1 · same meaning "mahādehāyai" is the dative of "mahādeha" — the same word in a different grammatical case.
Dictionary citations
Monier-Williams (1899) · महादेह (linked stem)
mahā—deha mfn. having a great body, Bhpr.
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