the theory that a political event in one country will cause similar events in neighboring countries, like a
falling domino causing an entire row of upended dominoes to fall.
Hope this help
What is domino theory in simple words?
The domino theory was a Cold War policy that suggested a
communist government in one nation would quickly lead to
communist takeovers in neighboring states, each falling like
a perfectly aligned row of dominos. Aug 24, 2018