# SIAM

/ˈsaɪæm/ (US) · CEFR C1 · Noun

Source: https://englishreference.com/word/siam
Updated: 2026-05-08

## Definition

the old name for the country we now call Thailand. It was used until the middle of the 20th century.

For teachers: the historical name for the Kingdom of Thailand, used officially until 1939 and briefly again between 1945 and 1949.

## Examples

- My grandfather has an old map that still shows the country as Siam.
- Historians studying Southeast Asian trade routes often refer to the region as Siam when discussing the 18th century.
- The diplomatic relations between the British Empire and Siam were formalised through various treaties that recognized the kingdom's unique position as a buffer state in the region.

## Usage notes

- Used as a proper noun to refer to the historical state; it does not take an article.

---

From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.