From Old French Jo(h)anne, and so a doublet of Joan. This too was revived as a given name in its own right in the first half of the 20th century. It has to some extent been influenced by the independently formed combination Jo Anne.
Basque: habitational name from any of various places in Biscay and Araba named Zabala, from Basque zabal ‘large’, ‘broad’ + the definite article -a. In some cases the surname may have arisen as a nickname from the same word.