What is "jacobins"

Dominican \Do*min"i*can\, prop. n. (Eccl. Hist.) One of an order of mendicant monks founded by Dominic de Guzman, in 1215. A province of the order was established in England in 1221. The first foundation in the United States was made in 1807. The Master of the Sacred Palace at Rome is always a Dominican friar. The Dominicans are called also preaching friars, friars preachers, black friars (from their black cloak), brothers of St. Mary, and in France, Jacobins.