resonance

Concise Oxford English Dictionary © 2008 Oxford University Press:
resonance/ˈrezənəns/

▶noun

• 1 the quality of being resonant.

• 2 Physics the reinforcement or prolongation of sound by reflection or synchronous vibration.

• 3 Mechanics enhanced vibration of an object subjected to an oscillating force close to a natural frequency of the object.

• 4 the condition in which an electric circuit produces the largest possible response to an applied oscillating signal.

• 5 Physics a short-lived subatomic particle that is an excited state of a more stable particle.

• 6 Astronomy the occurrence of a simple ratio between the periods of revolution of two orbiting bodies.

• 7 Chemistry the state of having a molecular structure which cannot adequately be represented by a single structural formula but is a composite of two or more structures of higher energy.