My partners grandmother recently passed and upon sorting her effects we found a naming certificate with a disturbingly apropos "spiritual name" documented that no one alive knew anything about

This has a coincidental poignancy due to my partner being 5 weeks away from giving birth.

The only thing is we have no idea what a spiritual name was/is and Google searches just returns lists of spiritual names from various religions and no indication why they would be on a child's naming certificate.

Hopefully this is the right place to ask, it's very important to us.