Definition of “resonance”

noun

1. the condition or quality of being resonant
2. sound produced by a body vibrating in sympathy with a neighbouring source of sound
3. the condition of a body or system when it is subjected to a periodic disturbance of the same frequency as the natural frequency of the body or system. At this frequency the system displays an enhanced oscillation or vibration
4. amplification of speech sounds by sympathetic vibration in the bone structure of the head and chest, resounding in the cavities of the nose, mouth, and pharynx
5. electronics the condition of an electrical circuit when the frequency is such that the capacitive and inductive reactances are equal in magnitude. In a series circuit there is then maximum alternating current whilst in a parallel circuit there is minimum alternating current
6. medicine the sound heard when percussing a hollow bodily structure, esp the chest or abdomen. Change in the quality of the sound often indicates an underlying disease or disorder
7. chemistry the phenomenon in which the electronic structure of a molecule can be represented by two or more hypothetical structures involving single, double, and triple chemical bonds. The true structure is considered to be an average of these theoretical structures
8. physics 
   1. the condition of a system in which there is a sharp maximum probability for the absorption of electromagnetic radiation or capture of particles
   2. a type of elementary particle of extremely short lifetime. Resonances are regarded as excited states of more stable particles
   3. a highly transient atomic state formed during a collision process