The domino effect is a chain reaction that occurs when a small change causes a similar change nearby, which then causes another similar change, and so on in linear sequence. The term is best known as a mechanical effect, and is used as an analogy to a falling row of dominoes. It typically refers to a linked sequence of events where the time between successive events is relatively small. It can be used literally (an observed series of actual collisions) or metaphorically (causal linkages within systems such as global finance or politics).
See also 
Relevant physical theory: