n.
 (pl. same)
   - dated a native of Siam (now Thailand) in SE Asia.
 - old-fashioned term for Thai (the language).
 - 
(also Siamese cat)
 a cat of a lightly built short-haired breed characterized by slanting blue eyes and pale fur with darker points.
 
adj.
 dated relating to Siam, its people, or their language.