English feminine form of John [q.v.], from Hebrew "God has been gracious".
In the Middle Ages Joan was the accepted feminine form of John, but was later superseded in popularity by Jane.
In old documents in Latin, the form Joanna or Johanna may be found, with appropriate case endings.
- A correspondent [LA] has pointed out that many [?most] earlier manuscripts used a common script for capitals "I" & "J". Thus Joan may have been written and then transcribed as Ioan. Many on-line services have transcribed original documents faithfully so this version might be the one to look for in the indexes to earlier records.
Another correspondent [MA2] reports that Siobhán is now commonly the Irish equivalent of Joan, certainly around the Wicklow area of Ireland. This usage is not reflected in our source books so any further examples would be welcome. The Scottish Gaelic equivalent is Seonag.
Jo may be used as a short form of Joan but we believe this is not a common diminutive.