name of Thailand before 1939 and from 1945-48, from Thai sayam, from Sanskrit syama "dark," in reference to the skin color of the people relative to whomever gave the name.
Entries linking to siam
Siamese adj.
"of or pertaining to Siam," 1690s; see Siam + -ese. Also from 1690s as a noun meaning "native of Siam." The original Siamese twins (exhibited from 1829) were Chang and Eng (1814-1874), Thai-Chinese natives of Siam who settled in the U.S. Hence Siamesed (adj.) "joined in the manner of Siamese twins" (1830). Siamese cat is attested from 1871.
Thailand
from Thai, indigenous name of the inhabitants, + land (n.). Also see Siam.