The name Mellie is a girl's name . Mellie and is often added to user-created lists like A List of Trendy Old Fashioned Names and discussed in our forums with posts like "Girls Makeover - Two Middles".
From the experts:
Mellie is not Millie and it's not Nellie, though it will forever be confused with those too more familiar nicknames. It's cute, too, and while some of the names it's usually short for may be sailing into the sunset (so long, Melody!), others like Amelia are rising through the ranks and may give Mellie a new chance to shine as a cute girls' nickname. Just be prepared for endless confusion.