Frau is in origin the equivalent of "My lady" or "Madam", a form of address of a noblewoman.
By the 1960s, this came to be seen as patronising by proponents of feminism, partly because there is no equivalent male diminutive, and during the 1970s and 1980s, the term Fräulein became nearly taboo in urban and official settings, while it remained an unmarked standard in many rural areas.
[2] This process was somewhat problematic, at least during the 1970s to 1980s, since many unmarried women of the older generation insisted on Fräulein as a term of distinction, respecting their status, and took the address of Frau as offensive or suggestive of extra-marital sexual experience.
[3][4] Nowadays, style guides and dictionaries recommend that all women be addressed as Frau regardless of marital status, particularly in formal situations.
[2] One area in which the word still sees wide use is in the form of an admonishing address towards girls until about their mid-teens, usually by a parent.