The name Isabelline is a girl's name . Isabelline and discussed in our forums with posts like "Last 2 Letters".
From the experts:
With the popularity of Isabella, you might think of Isabelline as a further elaboration -- though it would be the definition of gilding the lily. But Isabelline is also a color, an amorphous pale yellow-gray-cream most often seen in horses' coats or birds' plumage.