Source : Webster's Revised Unabridged Dictionary (1913)

Port-royalist \Port-roy"al*ist\, n. (Eccl. Hist.)
   One of the dwellers in the Cistercian convent of Port Royal
   des Champs, near Paris, when it was the home of the
   Jansenists in the 17th century, among them being Arnauld,
   Pascal, and other famous scholars. Cf. {Jansenist}.