Definition of ribat:
(n) :
(Islam, figurative) The duty of all Muslims to defend and/or retake Islamic lands.
(n) :
(chiefly historical, especially Islam) A border or frontier guardpost.
(n) :
(Islam) A Sufi monastery.
(n) :
(chiefly historical) A caravanserai or inn in, converted from, or resembling such a guardpost.
(n) :
(historical) The duty of some men to serve at such posts.
(n) :
(chiefly historical) An Islamic convent.