As a deity name
Name 554 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 night or day of full moon
Scripturally attestedWhy this matches what you typed
M1 · same meaning "pūrṇimāyai" is the dative of "pūrṇimā" — the same word in a different grammatical case.
Dictionary citations
pūrṇimā f. the night or day of full moon, Rājat.; Sūryas.
pūrṇimā, pūrṇimāsī, pūrṇamā The day of full moon; N. 2. 76.
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