react
v//ɹiːˈækt//reagera
(physics, intransitive) To return an impulse or impression; to resist the action of another body by an opposite force
(chemistry, intransitive) To act upon each other; to exercise a reciprocal or a reverse effect, as two or more chemical agents; to act in opposition.
(chemistry, transitive) To cause chemical agents to react; to cause one chemical agent to react with another.