American Dictionary of the English Language

REACT', verb transitive [re and act.] To act or perform a second time; as, to react a play. The same scenes were reacted at Rome.

REACT', verb intransitive

1. To return an impulse or impression; to resist the action of another body by an opposite force. Every elastic body reacts on the body that impels it from its natural state.

2. To act in opposition; to resist any influence or power.