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.

Authorities were also investigating the speed of the train and its braking distance, Siam added.

From Barron's • May 18, 2026

Tavatanakit had a three-round total of 16-under 200 on the Siam Country Club Old Course at Chonburi southeast of Bangkok.

From Seattle Times • Feb. 24, 2024

In case you were wondering, there is a Four Seasons Resort in Koh Samui, where guests can stay in private villas overlooking the Gulf of Siam.

From Los Angeles Times • Jan. 6, 2024

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

I learn that Burma is the largest country in Southeast Asia, that it borders India and China and Siam.

From "Orphan Train" by Christina Baker Kline

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