Other forms of the name in English are Jan, Jane, Janet, Janice, Jean, and Jeanne.
In Greek this name became Ιωαννης Iōannēs, from which Iōanna was derived by giving it a feminine ending.
[1] Saint Joanna was culturally Hellenized, thus bearing the Grecian adaptation of a Jewish name, as was commonly done in her milieu.
[2] At the beginning of the Christian era, the names Iōanna and Iōannēs were already common in Judea.
[3] The name Joanna and its equivalents became popular for women "all at once" beginning in the 12th century in Navarre and the south of France.