Elaboration of Mary, with the addition of the productive suffix -lyn (see Lynn). It is recorded in the 18th century, possibly as a blend of Mary and Ellen, but first came into regular use in the 20th century, peaking in the 1940s and 50s. Since then its use has been surprisingly moderate, considering the enduring popularity of the film star Marilyn Monroe (1926–62), baptized Norma Jeane Baker.
English and Welsh: patronymic from the Middle English personal name Jon(e) (see John). The surname is especially common in Wales and southern central England. In North America this name has absorbed various cognate and like-sounding surnames from other languages. (For forms, see Hanks and Hodges 1988).