The Collaborative International Dictionary of English v.0.48:

Cistercian \Cis*ter"cian\, n. [LL. Cistercium. F. C[^i]teaux, a
   convent not far from Dijon, in France: cf. F. cistercien.]
   (Eccl.)
   A monk of the prolific branch of the Benedictine Order,
   established in 1098 at C[^i]teaux, in France, by Robert,
   abbot of Molesme. For two hundred years the Cistercians
   followed the rule of St. Benedict in all its rigor. -- a. Of
   or pertaining to the Cistercians.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Cistercian
    n 1: member of an order of monks noted for austerity and a vow
         of silence [syn: Trappist, Cistercian]