Resonator
Is a device or system that exhibits resonance or resonant behavior. It naturally oscillates with greater amplitude at some frequencies, called resonant frequencies, than at other frequencies. The oscillations in a resonator can be either electromagnetic or mechanical (including acoustic). Resonators are used to either generate waves of specific frequencies or to select specific frequencies from a signal. Musical instruments use acoustic resonators that produce sound waves of specific tones. Another example is quartz crystals used in electronic devices such as radio transmitters and quartz watches to produce oscillations of exact frequency [wikidoc.org].
Acoustical devices for reinforcing sound include the sounding board of a piano, the “belly” of a stringed instrument, the air mass of an organ pipe, and the vocal animal's throat, nose, and mouth cavities. In addition to augmenting acoustic power, resonators may also change the quality of a tone by altering the relative intensities of overtones. The Helmholtz resonator is an enclosed volume of air communicating with the outside through a small opening. The enclosed air resonates at a single frequency that depends on the volume of the vessel and the geometry of its opening. The term resonator also denotes a system of electrons within a molecule or ion that absorbs electromagnetic waves of particular (resonance) frequencies [Online Encyclopedia Britannica].
An instrument for detecting the presence of a particular frequency using resonance [Dictionary.com].
Resonator. wikidoc.org. Retrieved from: https://www.wikidoc.org/index.php/Resonator
Resonator. Online Encyclopedia Britannica. Retrieved from: https://www.britannica.com/science/resonator
Resonator. Dictionary.com. Retrieved from: https://www.dictionary.com/browse/resonator