Freiherr
Freiherr (German), a term in use since the late 14th century for a dynastic lord not bound by service to a superior; it is now the title held by nobles ranking immediately below Graf (count), corresponding to the rank of baron. The wife of a “Freiherr” is styled “Freifrau”, while his daughter is called “Freiin” or “Freifräulein”.
Source: Meyers Großes Konversations-Lexikon, 6. Auflage 1905–1909