The name Soleil is a girl's name of French origin meaning "sun". Soleil and is often added to lists like French Word Names and discussed in our forums with posts like "Baby a Day".
From the experts:
An attractive French word name known here via former child TV star Soleil Moon Frye, aka Punky Brewster. It started to be lightly used in the U.S. in the 1920's, and is now attracting some attention as both a sunny nature and an exotic name. It's currently Number 680 on Nameberry.