[Jac.o.bin] n [ME, fr. MF, fr. ML Jacobinus, fr. LL Jacobus (St. James); fr. the location of the first Dominican convent in the street of St. James, Paris] (14c) 1: dominican
2. [F, fr. Jacobin Dominican; fr. the group's founding in the Dominican convent in Paris]: a member of an extremist or radical political group; esp: a member of such a group advocating egalitarian democracy and engaging in terrorist activities during the French Revolution of 1789 -- Jac.o.bin.ic or Jac.o.bin.i.cal adj -- Jac.o.bin.ism n