Here are some Jain girl names that start with the letter Y, along with their simple meanings in a Jain context:

• Yamika — related to night; sometimes used to denote a gentle, calm nature
• Yamini — night; often interpreted as serene or peaceful like the night
• Yashvi — famous, renowned; associated with inner luster or spiritual glow
• Yashika — one who brings or holds fame; a bearer of merit
• Yashoda — (note: widely known from Hindu tradition, but some Jain families use it; means “one who helps or nurtures joy”)
• Yaśnavi — radiant with glory
• Yanika — a seeker or one who moves with quiet spirit
• Yagnika — one who performs or embodies yajña (sacred ritual; symbol of auspicious action)

A couple of cautions:

• Some names overlap with broader Indian or Hindu traditions, so if you want strictly Jain-identified naming, you may prefer to stick to meanings that emphasize virtues like renunciation, modesty, compassion, or spiritual focus.
• Traditions differ between Digambar and Shwetambar communities, so a name's popularity or acceptance can vary by region or lineage.

If you’d like, I can narrow this list to strictly Jain-specific meanings or search for JainKnowledge.com pages with more details.