The name Flossie is a girl's name of Latin origin meaning "flourishing, prosperous". Flossie and is often added to lists like Vintage Nicknames for Girls and discussed in our forums with posts like "Gender Bender Makeover Game".
From the experts:
Flossie was an extremely popular Florence nickname that was used independently in the early twentieth century, given to over five hundred girls per year a century ago. Flossie was one of the younger twins in the iconic children's book series The Bobbsey Twins, first published in 1904. Appealing, if a little cutesy--sweet as candy floss. A similar name is Florrie.