Allah the Most High said in the Noble Qur'an:
يَا أَيُّهَا النَّبِيُّ قُل لِّأَزْوَاجِكَ وَبَنَاتِكَ وَنِسَاءِ الْمُؤْمِنِينَ يُدْنِينَ عَلَيْهِنَّ مِن جَلَابِيبِهِنَّ ذَلِكَ أَدْنَى أَن يُعْرَفْنَ فَلَا يُؤْذَيْنَ وَكَانَ اللَّـهُ غَفُورًا رَّحِيمًا
O Prophet! Tell your wives and your daughters and the women of the believers to draw their cloaks (jalaabeeb, pl. of jilbab) all over their bodies (i.e. screen themselves completely except the eyes or one eye to see the way). That will be better, that they should be known (as free respectable women) so as not to be annoyed. And Allah is Ever OftForgiving, Most Merciful.
[Quran 33:59, translation of the meaning Hilali & Khan]
The Jilbaab in Shari'ah is what women wear in the form of a cloak that covers the entire body from head to toe. Unlike some of the styles of garments that are popularly known and worn today among the muslim women, the Jilbaab for women is actually an outer garment that starts from the head, not the shoulders. The definition of the Jilbaab is not clear to many sisters, so I would like to share a link to an ebook that I found very beneficial. The ebook is a compilation of statements of the Scholars throughout the ages on the definition of the Jilbaab in Shari'ah. It is a very important reminder for all of us and a detailed description of the proper Jilbaab. After reading this, nothing should remain unclear in sha Allaah. The link below opens in a new window or a tab.