siamese

Etymology

Siam + -ese

adj

1. Of, or relating to Siam; Thai.
   I remember one such occasion when a Siamese pupil had fired the train from Lime Street, and so complimentary were the Chief's remarks on the condition of the fire that we found our young Siamese friend difficult to live with for about a week afterwards! 1943 July and August, T. Lovatt Williams, “Some Reminiscences of the Footplate—1”, in Railway Magazine, page 235
2. Of a connection of tubes or hoses: shaped like the letter Y.

noun

1. (plural "Siameses") A Siamese cat.
2. (historical, plural "Siamese" or "Siameses") An inhabitant of Siam.
3. (plural "Siameses") A connection of tubes or hoses shaped like a letter Y.