Firstly: Defining Seclusion
I`tikaf linguistically: is intense interest in a thing and trapping oneself with it. It comes from: `akafa `ala al-shay' if he showed intense interest in it such that nothing else concerns or distracts him. From this it was to who is persistently in mosques performing devotional worship therein: `akif and mu`takif.
I`tikaf terminologically: is staying in the mosque with the intention of closeness to Allah, exalted, whether in the day or night.
Secondly: Purpose of Seclusion
There are many goals of seclusion; among those are: Making the heart accustomed to the worship of Allah, exalted. Having Him solely in one's heart and devoting one's body in His servitude. Being solely with Him, glorified in His majesty. Leaving off worldly worries and matters.
Thirdly: The Ruling if Seclusion
Seclusion is a sunnah for both men and women,  A woman may be prohibited from seclusion if there is no place for her in the mosque to cover herself, or she fears the temptation of the transgressors. Prohibition here is due to the Law-Giver preserving the woman’s dignity and honour, not as blanket ruling. and this is by agreement of the four schools of jurisprudence.  Except that, for the Hanafis, the woman secluding herself in her place of prayer at home, is better than her secluding herself in a mosque that holds a jumu`ah prayer.