what's the difference between frau and fraulein
Fräulein Fräulein is the diminutive form of Frau, which was previously reserved only for married women. Frau is in origin the equivalent of "Mylady" or "Madam", a form of address of a noblewoman. But by an ongoing process of devaluation of honorifics, it came to be used as the unmarked term for "woman" by about 1800. Therefore, Fräulein came to be interpreted as expressing a "diminutive of woman", as it were implying that a Fräulein is not-quite-a-woman. By the 1960s, this came to be seen as patronising by proponents of feminism, 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. 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.