It says in the halakha that a married woman may not go out into the public market place with "p'ruath rosh."
I have heard that this means "with uncovered head," but this does not seem to match up with the other uses of the term "p'rua" in the Gemara where it clearly means "disheveled/loosed."
In Masekheth Kethuboth (cf. Mishna, pereq 2, Gemara 15b-16b, 28a) it mentions a bethula coming out of the wedding canopy with her hair "p'rua" and goes on to explain that it means "loosed" and upon her shoulders and not simply "uncovered."
Additionally, the literal meaning of the word "p'rua" is "loosed/disheveled." So it seems that it begs the question that if Hazal meant to discuss hair which is either covered or uncovered why did they not simply employ the readily available terms of kisui and gilui, etc. Why did they choose a different word and give it an obscure meaning?