Sumatra

American  

[soo-mah-truh] / sʊˈmɑ trə /

noun

1. a large island in the W part of Indonesia. 164,147 sq. mi. (425,141 sq. km).

---

Sumatra British  

/ sʊˈmɑːtrə /

noun

1. Indonesian spellling: Sumatera.  a mountainous island in W Indonesia, in the Greater Sunda Islands, separated from the Malay Peninsula by the Strait of Malacca: Dutch control began in the 16th century; joined Indonesia in 1945. Northern coastal areas, esp Aceh province, suffered devastation as a result of the Indian Ocean tsunami of December 2004. Pop: 42 409 510 (2000). Area: 473 606 sq km (182 821 sq miles)

---

Sumatra Cultural  

1. Island in Indonesia in the Indian Ocean northwest of Java and west of Malaysia.

---

Discover More

Though much of the island is covered by swampland and impenetrable rain forest, Sumatra's industries — including oil, coal, gold, silver, rubber, timber, and tobacco — produce over half of Indonesia's income.

Other Word Forms

Derived Forms

• Sumatran
  adjective

Example Sentences

The only documented example occurred in Sumatra, where two large earthquakes struck three months apart in 2004 and 2005.

From Science Daily • May 2, 2026

Triggered by a rare cyclone in November, the deluge killed more than 1,000 people and displaced hundreds of thousands across the island of Sumatra.

From BBC • Dec. 25, 2025

Pictures showing the carcass of a Sumatran elephant, another critically endangered species, being swept away by floods in Aceh in northern Sumatra went viral on social media last week.

From BBC • Dec. 11, 2025

Monsoon rains paired with two rare tropical storm systems, sometimes known in the region as cyclones, dumped record deluges across Sri Lanka, and parts of Indonesia's Sumatra, southern Thailand and northern Malaysia last week.

From Barron's • Dec. 3, 2025

Chastened, they sailed on, but en route word reached them that Sumatra had fallen to the French and so they observed the transit inconclusively from the Cape of Good Hope.

From "A Short History of Nearly Everything" by Bill Bryson