Siam

American

[sahy-am, sahy-am] / saɪˈæm, ˈsaɪ æm /

noun

former name of Thailand.
Gulf of, Thailand.

Siam British

/ ˈsaɪæm, saɪˈæm /

noun

the former name (until 1939 and 1945–49) of Thailand
an arm of the South China Sea between the Malay Peninsula and Indochina the former name of (the Gulf of) Thailand

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Bangkok police chief Siam Boonsom said Sunday that there was traffic congestion at the crossing daily, but never an accident.

From Barron's • May 18, 2026

In a clothing shop in Siam Square, a commercial hub in Thailand’s capital, the happy couple excitedly eyed multi-colored garments as they discussed their potential wedding.

From Seattle Times • Dec. 19, 2023

Hamas said that he was killed along with three other senior militants, including Ayman Siam, who Israel says was in charge of Hamas’ rocket-firing unit.

From Washington Times • Nov. 26, 2023

Prime Minister Srettha Thavisin expressed condolences over the deaths in opening remarks at a technology event hosted by Siam Paragon, which reopened for business on Wednesday.

From Reuters • Oct. 4, 2023

Locke’s King of Siam case is one where a tacit reserve would have been appropriate, but Locke had not formulated one.

From "The Invention of Science" by David Wootton

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023