Pet form of Cynthia or, less often, of Lucinda, now very commonly used as a given name in its own right, especially in North America. It has sometimes been taken as a short form of the name of the fairytale heroine Cinderella, which is in fact unrelated (being from French Cendrillon, a derivative of cendre ‘cinders’).
English and Scottish: patronymic from the personal name John. As an American family name, Johnson has absorbed patronymics and many other derivatives of this name in continental European languages. (For forms, see Hanks and Hodges 1988.)