NOUN (3)

1. a member of the Sunni Muslim people living in northwestern Caucasia;

2. a mostly Sunni Muslim community living in northwestern Caucasia;

3. a northern Caucasian language spoken by the Circassian;

The Collaborative International Dictionary of English v.0.48:

Circassian \Cir*cas"sian\, a.
   Of or pertaining to Circassia, in Asia. -- n. A native or
   inhabitant of Circassia.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Circassian
    n 1: a member of the Sunni Muslim people living in northwestern
         Caucasia
    2: a mostly Sunni Muslim community living in northwestern
       Caucasia
    3: a northern Caucasian language spoken by the Circassian