Awrah means the portion where we have to cover..
For men, It is the portion between Navel and Knees..

For women,
While praying.., woman should cover her entire body except the face and the hands.
*On diff situation, womens awrah differs like while praying, when standing in front of a relative or non relative etc..

If i explain all these, it will start an other debate with some people who use their logics instead of Quran.
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http://www.youtube.com/watch?v=tjmNV6k9loU
rms..!!