The Collaborative International Dictionary of English v.0.48:

Albigenses \Al`bi*gen"ses\, Albigeois \Al`bi`geois"\, n. pl.
   [From Albi and Albigeois, a town and its district in the
   south of France, in which the sect abounded.] (Eccl. Hist.)
   A sect of reformers opposed to the church of Rome in the 12th
   centuries.
   [1913 Webster]

   Note: The Albigenses were a branch of the Catharists (the
         pure). They were exterminated by crusades and the
         Inquisition. They were distinct from the Waldenses.
         [1913 Webster]

WordNet (r) 3.0 (2006):

Albigenses
    n 1: a Christian religious sect in southern France in the 12th
         and 13th centuries; believers in Albigensianism [syn:
         Albigenses, Cathars, Cathari]