1A disorder found in troubled adolescents who perceive running away to be a solution to difficulties in the home, at school, etc.
2A chemical or nuclear reaction that is accelerated by the products of the reaction or its effects (such as a rise in temperature), so that it becomes uncontrollable and continues until there are no reactants left.
Origin
1930s.
Definition of runaway reaction in US English:
runaway reaction
noun
1A disorder found in troubled adolescents who perceive running away to be a solution to difficulties in the home, at school, etc.
2A chemical or nuclear reaction that is accelerated by the products of the reaction or its effects (such as a rise in temperature), so that it becomes uncontrollable and continues until there are no reactants left.