golden triangle

Collins Concise English Dictionary © HarperCollins Publishers::

golden triangle noun

1. the Golden Triangle ⇒ an opium-producing area of SE Asia, comprising parts of Myanmar, Laos, and Thailand

WordReference Random House Unabridged Dictionary of American English © 2026

Gold′en Tri′angle, 

1. Place Names (sometimes l.c.) an area of Southeast Asia encompassing parts of Burma, Laos, and Thailand, significant as a major source of opium and heroin.
2. British Terms, Place Names [Canadian.] the peninsula enclosed by Lakes Ontario, Erie, and Huron.