<p><strong>Adjective:</strong></p><ul><li>Of or relating to Siam, its people, or their language.</li><li>The former term for Thai.</li><li>Twin; closely connected; similar.</li><li>Informal: dual; combined; twofold or two-way.</li></ul><p><strong>Noun:</strong></p><ul><li>Plural: Siamese.</li><li>A native of Siam.</li><li>Former name of Thai.</li><li>Siamese cat.</li><li>(usually lowercase): a standpipe placed outside a building close to ground level, having two or more openings so that fire engines can pump water to the sprinkler system of the building.</li></ul>