golden triangle

Short definition from Wiktionary

Noun

1. 1
   An isosceles triangle whose duplicated side is in the golden ratio to the distinct side.

Proper noun

1. 1
   Any region of prosperity, influence, etc. bounded by three points: A geographic region of Thailand, Laos and Myanmar, known for its production of opium and heroin.
2. 2
   Any region of prosperity, influence, etc. bounded by three points: A region of Victoria, Australia, where the Victorian Gold Rush occurred.
3. 3
   Any region of prosperity, influence, etc. bounded by three points: A region of New South Wales, Australia, where prime agricultural land occurs, particularly for cereal crops, and from which golden sheaves of wheat are harvested.
4. 4
   Any region of prosperity, influence, etc. bounded by three points: An area of Paris, France, located between Avenue Montaigne, Avenue des Champs-Elysées, and Avenue George V.