domino theory

American  

noun

1. a theory that if one country is taken over by an expansionist, especially Communist, neighbor, party, or the like, the nearby nations will be taken over one after another.

---

domino theory Cultural  

1. The idea that if one key nation in a region fell to control of communists, others would follow like toppling dominoes. The theory was used by many American leaders to justify American intervention in the Vietnam War. (See policy of containment.)

---

Etymology

Origin of domino theory

First recorded in 1960–65

Example Sentences

What about the influence of the domino theory, a key Cold War doctrine, on his decision-making?

From Washington Post • Jul. 1, 2022

Wells said he and his fellow midshipmen saw the Vietnam War in terms of the domino theory regarding communism in southeast Asia.

From Washington Times • May 20, 2017

The domino theory, you know, if Vietnam goes, China, da, da, da, da, da, da, da.

From New York Times • Feb. 11, 2016

President Eisenhower described this threat in terms of the domino theory.

From Textbooks • Jan. 1, 2012

Brew said the same thing about the domino theory.

From "Fallen Angels" by Walter Dean Myers