The name Joanne is a girl's name of French origin meaning "God is gracious". Joanne and is often added to lists like Variations of John and discussed in our forums with posts like "Get To That Nickname".
From the experts:
A Top 100 name from the 1930s all the way through the 1950s, it's now firmly in Mom -- or Grandma -- land and supplanted for babies by Joanna.....or even great-grandmother Josephine. In its heyday, it had a host of variations, including JoAnn and Jo-Anne.