The name Winslet is a girl's name meaning "Wynn's channel or stream". Winslet and is often added to lists like Celebrity Surnames as Firsts and discussed in our forums with posts like "Build a sibling set together!".
From the experts:
Winslet is one of a legion of surnames newly considered fair game as first names. The inspiration may be British star Kate, but she's not the only reason parents are attracted to Winslet, one of those British girl names that sounds at once classy and winning. Yet be warned that if you choose this, people will forever assume you are major fans of the actress. Other Win- beginning names up for new consideration: Winslow, Winston, Wynton, Winifred and Winnie, along with just plain Win or Wyn or Wynn.