It's most likely a modern feminization of
Jeffrey, using the suffix -yn (as in
Jacquelyn,
Carolyn, etc.)
Alexandrina, Annabella, Clementine, Charlotte, Emilienne, Florence, Frederica, Katharina, Mary (May), Maud, Penelope, Rosamund, Theodora (Teddy).
Aubrey, Axel, Benedict, Bertrand (Bertie), Cuthbert, Dashiell, Everard, John (Jack) Leopold (Leo), Magnus, Matthias, Maximilian (Max), Wilfred.This message was edited 7/2/2016, 6:15 PM