baroness
Refers to the wife of a baron or a woman holding a baronial title in her own right. Used in historical or European aristocratic contexts.
She was known in society as a baroness.
男爵 is the title 'baron', while 男爵夫人 specifically refers to the baron's wife or a female baron.
Compound of 男爵 (baron) and 夫人 (wife, lady). The term follows the pattern of European aristocratic titles adapted into Japanese.